steamin'

I took my 96 Accord to a big box place for an oil change. Afterward,
on an extended trip, I noticed an oil leak and took it to a local
mechanic to have it inspected. He showed me that there is a
significant crack just beneath the drain plug running in a straight
line and ending in a place where the metal is bent into the pan.
Looking at it from the inside, it is plain that the crack runs along
the triangular reinforcement plate, then out about half an inch.

The big box guys said that the leak was caused by a stripped oil plug,
but the threads are perfect. Then they said 'the Incredible Hulk
couldn't overtighten this plug without it stripping before the pan
cracked'. Every other mechanic I've looked at has said it is a plain
case of overtightening, but I want to confirm that this isn't some
wide or known problem. Any thoughts?