Running an 0-235 well beyond TBO

How common is this? I am seeing some 152s for sale with engines as high
as 3000 hours SMOH. Surprising. (Well, to me!)

Related question (probably nearly impossible to answer): to what degree
is an engine's reliability related to it's time SMO? Obviously, it has
to be that a Lyc at 2200 hours is more likely to fail than one at 200,
but what are people's opinions? My FBO did just tell me of a gent who
had his O-320 put a rod through the crankcase at 140 hours.. and
apparantly Lyc isn't covering it. And this wasn't a hangar queen
sitting for years either.

Still lookin for the right plane. Since I'm going to be out of the
country for 9 days starting Friday I've held off on moving on anything.