The "do you tip" comes up in various areas for example my last visit to Newmar, the tech did a great job (until I found damage they'll be repairing after I returned home) so I asked others if they tip techs during service visits. This comes up for factory pickups and typically the answer is yes, if you want, for that. For service visits, I have never, the answer I got from others was NO. If it makes you feel better do it, if the service was above and beyond, consider it. My concern would be is conditioning workers to expect tips and then those that don't stand out and may not receive good service after that point. I remember being in grocery stores or establishments that put up signs either so and so accepts tips or not to tip which takes the pressure and wonder out of the question.