What prompted this question is a personal gift to a member of the clergy.
A friend's parents were multi-millionaires. Before they died, they gave millions to Boston College and the Catholic Church (The mom had 6 priests and a bishop at her funeral) and other charities. But in addition, the mom gave money directly to certain priests who had assisted her in her final years. The priests, in turn, used the funds for their personal use like a Rolex Watch, Mercedes, first class tickets to Hawaii for themselves. One priest alone received over $300k over the course of five years.
Isn't this similar to a waiter's tip? The gift was given as a reward for services rendered, just like a tip. Unlike a waiter's tip, however, these gifts are not normally expected.
Other than a waiter's tip, at what other transactions is a discretionary gift considered income to the recipient?