Tip lines are a tricky thing. A tip line, in case you can’t figure it out, is the joke or witty comment you use to let your group know that you graciously accept tips for your work. Most jobs that are tip-based don’t need a tip line because it’s common knowledge that giving the worker a little gratuity, is the proper thing to do (think bartender, server, uber driver), but unfortunately, tour guides don’t fall into that category. Perhaps it’s because there are some tour guides who work at places where tipping isn’t allowed (these are usually prestigious places like Thomas Jefferson’s house and such). Or perhaps it’s because not…