I can see your viewpoint, but I disagree. In my opinion there are multiple forms of guilt tripping. I don't necessarily agree with the OP on this one, but when you say "tips appreciated" you do kinda put the expectation out there even if you don't mean to. If you say tips appreciated people are more likely to tip, it's more meant as a reminder imo but I can understand how it affects people too. When someone says "tips appreciated but not necessary", I can see how someone would worry because technically it's more meant for people who couldn't afford to tip.