One time, long long ago, I was on a flight from SAN to SFO on PSA. I had a reserved seat, (I think it cost me about $20). Just before push back the CSA came on looking for volunteers to give up their seat. He held up a crisp $100 and asked the cabin. I was temped but wanted to get home for Xmas. As no one volunteered, he held up another crisp $100 and asked again. I jumped up and took the offer. They put me on the next flight. I was delayed about 3 hours. Ah, the good old days!