About 2 months ago, I went out to eat at a local, non-authentic mexican place with my boyfriend and his mom. We are all ordered drinks- she ordered a medium blended margarita, he ordered a medium pina colada, and I ordered a medium margarita made with only Cointreau, tequila, and lime. When they were delivered, they both got what they ordered, while I got a large margarita. I assume it was indeed the sour mix-free margarita since there was no evidence to the contrary. I was distracted when the drink arrived, and by the time I noticed the mistake, the server had disappeared. The glasses for medium vs large drinks were very different so there was no doubt that I had been served the wrong size.
Our server failed to reappear, so we flagged down another server and told him about the mistake. He took my glass and fetched our server who returned new minutes later with a margarita in the proper glass. He then told us that he had given me the larger size intentionally, but since we had spoken to a different server, he had to get the drink switched out. I felt guilty because it initially seemed that I had accidentally rejected a kind gesture, but the situation was just a bit strange, and made me wonder if he had given me the larger drink in hopes that I would just drink it and he could charge me for it on the bill. It seems to me that if he had wanted to give me the largest thing as a treat, he would have mentioned something about it, so that I wouldn't question his motives or believe he had made a mistake.
Any thoughts on the matter? The drink wasn't great, and the food was worse, so I have no intentions of returning to see if the same thing happens.