No hi-jacking,dude, good question.....The springer, or break barrel air guns have a unique two-stage kick, there's the normal push backward, then followed by a forward thrust when then cocked spring/bolt slams against whatever it slams against.It's this forward thrust that's most damaging.
( please forgive this less than technical explanation, but you get the idea.) Most scopes are not designed to handle this,even many otherwise high quality ones, and, from what i've read and been told, the reticle breaks loose,in some cases,after just a relatively few shots.
Some manufacturers, like Burris and Leupold, claim that all their scopes are air-rifle rated, but with some companies, it's only certain ones. The Bushnells, the Elite line in particular, are pretty highly advertised as being built to withstand the stresses of air gun use, and are commonly seen on high-end air-rifles.
And thanks for the response tommer, but from what i've gathered, parallax is the biggest concern at very long distances ( 700 yards +) and very short distances, which may be why AO's seem to be on virtually all airgun scopes.