Upvote:4
I'm not an expert on the ESTA and VWP, but from what I understand, if you leave the USA for Canada or Mexico and return via Canada or Mexico you don't need to be stamped again as it is considered part of the same trip. This was certainly the case for us when we went back and forwards between Canada and the USA a few times on our last trip. We were only stamped on first arrival into the USA and into Canada. The subsequent ones, they just checked our passports, did the usual entry/exit scans and that was it. So the below happened on our trip:
We were only stamped once for entry into the USA, and that was on our first arrival.
I believe this is normal practice.