How does a thief know whether an ATM is EMV enabled or not?
So, here in Europe, ATMs have been Pin&Chipped for at least since the mid 90's. So there's no question.
Other than that:
- Just insert a credit card (stolen, yours) and try to get money?
- Stand next to the ATM and observe people withdraw money?
- find the type label and get the user manual online?
Also, although admittedly small in-shop ATMs are far more common in the US, and thus are offline / non-chip ones, you could probably compile a list of those which have and those models which don't have that feauture. I'm not a skimmer, but common sense tells me that there's a list with pictures somewhere on the internet.