I ran a surprise round zero before I realized that it wasn't a thing.
I always stop people from wanting the bonus action potion drinking by saying, "Sure. Drinking itcan be a bonus action, if it's already in your hand. But then I am going to enforce every little thing about what is in your hands. Or you can spend an action and we'll assume that you clear your hand, get the potion, drink it, store (or drop) the bottle, and get your weapon/wand back into your hand. Which would you rather? (They usually pick action potion).