Last year, I gifted 2 std award tickets to my customers. They were standard US Domestic award tkts.

On returning from BOS to the west coast on a early morning flight, they were told at the airport that flights were overbooked for most of the day, and that they had been bumped. No advance info was given.

However, UA did provide them with complimentary stay at an airport hotel (Sheraton ?) without too much problem and gave them food vouchers as well ($7 per meal )

Maybe things have changed since then ?