I agree that they're well aware.
I once got stopped at self checkout because I put two vegetables (peppers, IIRC) of different types in the same bag and weighed them together.
They were the same price so it's not like I was trying to pull a fast one one anyone, but "the system" noticed and flagged me for someone to come over.
This was pre-pandemic, and I'm sure they're not less capable now than before.