I understand. Chip/PIN security only works on Chip/PIN cards. Non-chipped cards are either being inappropriately denied, properly approved, or approved without signature or other verification. So, yes, I agree that in many cases security of non-Chip/PIN cards is reduced in some places where Chip/PIN has been implemented at the merchant level.

Automated pay stations do one of the following for non-Chip/PIN cards.
1) Require a PIN. Do not recognize any PIN and deny all transactions.
2) Require a PIN, but accept any four digit combination for non-Chip/PIN cards (as no verification can occur without the chip).
3) Recognize the card is chip-less and skip the PIN business.
4) Provide an option to skip the PIN entry and approve based on mag stripe data/bank authorization.

At an in-person merchant, terminals may do similar things. With merchant terminals, the merchant is supposed to have a way to avoid PIN requirements for non-Chip/PIN cards. I recognize that some clerks may not know how to do so. The terminals sometimes provide a no-pin button for the customer to press, sometimes ignore an entered PIN (as above with automated pay stations), sometimes deny without cashier intervention.

I agree that the situation is a mess, and it really is inexcusable that Visa/MC have let it get this way.