Any book that gets mad at you have NO clue how to book and I would get the hell out fast. Here is why...
If a line opens up at -150/+140 and you play the fav at -150.. Then by evening the steam comes in heavily on the fav and the line closes at -175/+165.. Now if you bet the dog at +165 and get yourself a 15 cent scalp (-150/+165) then all you just did what was lower your rate of return on the bet because you just gave the book a bet on the real line of +165, rather than keep a single bet at -150 instead of -175 and have a 25 cent advantage. The book is way better off seeing you have a 15 cent scalp and hope the fav wins, and win you nothing, than have you have a game at 25 cents better than the real line. By scalping with the book, you just screwed up your big return on the dollar, and books actually get pissed at this. Plus, what is difference if you bet it at +165 after, or someone else bets it? That is their line and they are looking for action on that game anyway or else they wouldn't be carrying that line.
I really think it all boils down to you outsmarting them and making them look silly at their game that you are a step ahead of them. It all boils down to pride, because I too used to get mad when a player would do this to me and I didn't like it all because I felt this player was mocking me, and he thought he was smarter than me.. But I was NEVER upset when he did it business wise. It's a bad move to scalp it for the bettor as the better move would be to just keep the strong side and let it ride.