If they're dumb enough to use the same hotspot from the same location over and over, sure.
That's not the only weak link in that strategy. On the top of my head, patterns come to mind. The date/times you do - whatever questionable activity - you're doing, the way of doing it(say, your unique words, posting style, etc) all create a unique fingerprint of you. All they have to do is match it with your logged in(Google,MS,etc) data habits.
I guess the best way to be anonymous is to be schizophrenic.
People that used that method have been caught.