Excessive "lost connection" log messages

Can you please attach a part of the logfile to see what has happened short before ?

Nothing happens shortly before, at least nothing related to these lost connections. Sometimes they are accompanied by "Took too long to log in" but not always.

For example, here is some of the log file from just now (#REDACTED-IP## is alway the same IP in this short example):

2013-02-21 00:19:15 [INFO] <##REDACTED-USER##> are you running 32 bit java?
2013-02-21 00:19:21 [INFO] <##REDACTED-USER##> mmhm
2013-02-21 00:19:52 [INFO] <##REDACTED-USER##> hmmm.....
2013-02-21 00:19:54 [INFO] <##REDACTED-USER##> i think i didnt download latest
2013-02-21 00:21:28 [INFO] <##REDACTED-USER##> man, this place is gonna look badass in the snow when I get it finished.....least I hope
2013-02-21 00:22:00 [INFO] <##REDACTED-USER##> wat r u building a house?
2013-02-21 00:22:10 [INFO] <##REDACTED-USER##> snow fort
2013-02-21 00:22:16 [INFO] <##REDACTED-USER##> ah
2013-02-21 00:22:54 [INFO] <##REDACTED-USER##> :Y i just started on my house
2013-02-21 00:22:56 [INFO] /##REDACTED-IP##:10234 lost connection
2013-02-21 00:23:05 [INFO] <##REDACTED-USER##> was gonna build it around a frozen lake, populate it with snow golems and maybe an ice palace
2013-02-21 00:23:26 [INFO] /##REDACTED-IP##:10081 lost connection
2013-02-21 00:23:31 [INFO] <##REDACTED-USER##> my houses are always small, just basic stuff really
2013-02-21 00:23:38 [INFO] /##REDACTED-IP##:54916 lost connection
2013-02-21 00:23:42 [INFO] <##REDACTED-USER##> my old continent had to many ppl on it
2013-02-21 00:23:51 [INFO] <##REDACTED-USER##> that sounds pretty boss
2013-02-21 00:23:58 [INFO] Disconnecting /##REDACTED-IP##:58367: Took too long to log in
2013-02-21 00:24:23 [INFO] <##REDACTED-USER##> thanks, I just hope I have the patience to go through with it
2013-02-21 00:24:26 [INFO] /##REDACTED-IP##:54925 lost connection
2013-02-21 00:24:39 [INFO] <##REDACTED-USER##> and that none of my neighbors are griefers -_-
2013-02-21 00:25:20 [INFO] /##REDACTED-IP##:59578 lost connection
2013-02-21 00:25:49 [INFO] /##REDACTED-IP##:59572 lost connection
2013-02-21 00:25:49 [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
2013-02-21 00:26:23 [INFO] <##REDACTED-USER##> man this texture is amazing i really need to fix it

In the above example, ##REDACTED-IP## first appeared on the 19th from a user with an outdated client. Since that time, this one user has generated 63 log entries.

As you can see from the example on the 21t, the log has regular user activity, peppered with mostly unrelated lost connections from random IP addresses. For the 20th, there were about 800 unique IP addresses recorded as lost connections. But in that timeframe, those 800 IP addresses generated 5000+ repeating lost connection messages.

I've looked up a few of the IP addresses and found that many (not all) belong to past users, like the example ##REDACTED-IP##. My current theory is that many of these lost connections are coming from Minecraft clients just looking to see if my server is up (queries to see and what version, motd, etc.). Basically, they are clients pinging my server just because my server is in their multiplayer list. They tried to connect once or twice, then they moved on but never deleted my server from the list.

Many people add my server to their server list who cannot log in because they don't know how to install the snapshot, and they never bother to delete my server. So they have 1.4.7 and they ping my server but never log in. I think the server is logging the pings to some extent as lost connections.

I don't care if they leave my server in their list, that's not a bug. I don't really care if they ping it, that's not a bug either. If pings present a problem in the future, it's my problem, not a problem in code. The bug here is: I just think the lost connections messages are too excessive.

This may or may not be related, but the console reported this around the same time as a lost connection (though it doesn't happen every time and did not get written in the log):

java.net.SocketTimeoutException: Read timed out
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.read(SocketInputStream.java:150)
        at java.net.SocketInputStream.read(SocketInputStream.java:121)
        at java.net.SocketInputStream.read(SocketInputStream.java:203)
        at java.io.FilterInputStream.read(FilterInputStream.java:83)
        at eg.a(SourceFile:184)
        at ch.i(SourceFile:250)
        at ch.c(SourceFile:16)
        at ci.run(SourceFile:94)

Can confirm this a bit: On my local server I'm getting a "lost connection" without being connected, just by opening the multiplayer world selection screen on the client:

2013-02-21 19:30:49 [INFO] /127.0.0.1:63573 lost connection
2013-02-21 19:31:33 [INFO] Kumasasa[/127.0.0.1:63601] logged in with entity id 41 at (-1741.507092258731, 73.0, -559.462920680532)
2013-02-21 19:31:36 [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
2013-02-21 19:31:40 [INFO] Kumasasa lost connection: disconnect.quitting

Behavior still present in 13w09a.

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.