I’ve also seen fake money passed off by religious people that looks fully real on one side, and has church propaganda on the other side.
You should ask restaurant staff how they feel about those tracts.
In any case, passing it off as a tip; you’ll only be breaking the law if it’s “real enough”. You will be decried as an asshole, though. if you don’t want to tip, just don’t tip. if your congregation is watching who puts what into the collection plate, maybe you should find a new congregation- they sound like assholes. (especially because a lot of places have ways of donating/tithing online.)