Ah, people don't like him because if they muck around in Denver too much, there is a chance of becoming dragon chow. But, seriously, just stay off the scopes in Denver, and you have less of a chance of randomly running into him than you do of accidentally bumping into any other dragon. Besides, Denver sucks to run in. Too many national borders to worry about, and subtle law changes you have to keep track of. Not to mention running around with that many fake ID's, at least three for each nation, just in case, and it becomes a huge charlie foxtrot to run properly. Best to just visit, and get out quick. So, really, no reason to stick around and rankle the big dragon when he comes back. And there are easier places to run, for more money, with less serious competition.