you'd be suprised how much flex glass has, and how much pressure it can take.
if your worried, glue a strip across the top of the front panel from end to end.
the front panel on my 100gallon bows about 1/3 " in the middle
to answer the question in the thread title, no, but i've seen a 29 gallon bust and spill all over my mates carpet floor because the stand was twisted about an inch out of whack. fool
Cynotilapia afra 'Cobue'
Pseudotropheus acei 'Msuli Point'
Aulunocara stuartgranti 'chipoka'