Corrected entry: The sale of such a large amount of Pseudoephedrine tablets to Howard would not have been allowed as it probably would have exceeded the daily and monthly limits of Pseudoephedrine sales to a single person as stated under US and Ohio law.
Corrected entry: Throughout the show, the character's lockers continually change position. For example, Rachel's locker is at first near the end of a row, a few down from Quinn's, yet later it's in the middle of the row, nowhere near any of the other Glee kid's lockers, and even later it's the second one down in a completely different row.
Correction: Students can request that they be moved to a new locker if theirs is too far away from their classes or someone might be bullying them at their lockers. Given how often the Glee kids are pranked and/or bullied, they probably have to move lockers frequently.
Correction: It is indeed not allowed, which was why Howard was arrested when trying, rendering this whole post pointless.