very annoying, also makes jumping off mountains too easy.
However, its not a bad idea to rename a stack of blocks cheaply; forcing users to individually rename dirt for example in an adventure map would be tedious for map makers, I have no idea why you would want a stack of swords unless they were all the same, again this is only relevant for map makers who would be the only people to use this.
Lol, I designed the same sugarcane farm and recently started having this problem, It is very annoying; before I had a 95% collection rate, now its about 40%