I took the greyhound from NYC to Toronto
At buffalo, it was 5 am in the morning, they just asked me and my wife, so are you landed PRs ...I said yes, then they asked how long since we were in the US , I said a few weeks...all this while I was
trying to get my passports and landing papers out of a folder,
by the time I took them out..they said ok ...proceed.
Next day I was walking on the rainbow bridge and accidently crossed past the canadian side...while trying to come back the lady asked
if I was a landed PR ..i said yes, did I have my papers...I said yes,
thats it...no other check I was let in !