[mwebb]

...."
We don't have emissions inspection around here, but I was referring to current tail pipe emissions standards. Nothing to do with visual testing. Around here (and in many other places) it's very easy to replace the cat with a lesser (hollow) version of itself and still pass emissions testing, including the visual portion."....

what you describe above
is a violation of federal law , in New York state it is good for a $10,000 fine .
i dunno about other states or locations

without a cat converter
an OBD2 system will not pass any emissions test that i am aware of anywhere in USA .
assuming the car has not be configured for a tighter emissions standard
like a - Partial Zero Emissions Vehicle -
OBD2 is the minimum ...."current tail pipe emissions standard"...