All posts need to have the same title: me_irl it is allowed to use an emoji instead of the underscore _
If you saw them multiple times, they almost certainly saw you. And realised that you were avoiding them. If you see someone you don't want to talk to just say "Hi, sorry can't stop to chat, I'm in a hurry." and move on. Much less awkward for all involved.
they almost certainly saw you
Nah, there's not enough info to know that or even assume it. People are not perfectly aware of their surroundings or others looking at them
Hence "almost". There's no reason to assume that the person OP was avoiding was any less aware of their surroundings than OP.
PSA: if you do stop to talk to someone at the supermarket, don’t do it in the middle of the fucking aisle. Between you, your friend and your respective carts, you create an obstruction for everyone else who just wants to get their damn groceries and get out.