I kept my Australian bank issued Visa card for a while when I first moved to Thailand, and used it while we were getting stuff set up locally. Even though it's never presented locally, with that card cashiers would often get the "sign or pin" prompt on the terminal, and then ask me (or gesture if their English wasn't great), and I'd usually pick pin, which would then produce a slip with "No signature required" printe…
Signing actually helps against fraud: Signatures can be compared, PINs cannot – and you can be made liable … :(
I had something similar years ago in Australia. I went into a branch, my signature had changed a LOT, and I couldn't match the old one. So they promptly updated my signature on file, based purely on the fact that I had my card and knew the pin (I don't even remember showing them my ID).