Can I turn my Cats on and OFF

My car has already been tuned by someone with LS1 edit and I am having trouble getting my car through inspection. When I spoke with the person who tuned my car they stated they turned my Cats off completely (whatever that means). I guess my question is can I turn my Cats on/off with HP Tuners?

Oh I don't get any codes for my Cats. So I don't know if he deleted the system of if he just deleted the codes or what. What do most tuners do to handle a car with no Cats? I also have to pass OBD II State inspection.

my guess is they are talking about Cat Overtemp Protection (COT). Turning it off doesn't generate any codes, it disables fuel enrichment at high cat temps. Increasing the likelihood of your cats burning out sooner, or at the extreme - melting.

-How- you "turn off cats" makes a difference to the
OBDII inspection. There's two ways to go - disable
the test (naughty, naughty) or leave the test enabled
but disable the "sets code" (sneaky sneaky). Check
that out in the Engine Diagnostics fields.

Sooner or later I expect they'll catch wise but this is
how I understand it is, today (or rather, last time I
read about it).