I totally agree. It would be better to ask customers if they wish to leave a tip. Telling them it is “customary” to leave a tip is not true and kind of “guilts” customers into leaving one. Besides, I do not appreciate charging the buyer a service fee for the tip when they already paid a service fee when purchasing the service. Also, recording artists, for instance, have so much to pay for: creation of the instrumental, recording of the vocals, hiring of one or more background singer (in quite some cases), vocal engineering, mixing, mastering, creation of the record artwork + all the paid promo, photoshoots, production of music videos, tours, transportation, accommodation, etc. Buyers should be allowed not to tip or to tip accordingly to their means without any guilt.