We didn't add additional tips in a 3 day stay and the servers recognized us, but service didn't change at all, so I wouldn't worry about it. When we ordered alcohol we tipped as appropriate.

Also we brought our own rum to the pool each day in the Ventana water bottles. Staff saw us mixing with soft drinks and made a joke, but said it was fine. We did also order 1 alcoholic drink at the pool per person and tipped on it. You could always just pre-mix with the free sodas in your fridge, or pour a beer in the water bottle, if you're afraid of the staff seeing.

We liked the deserts at dinner, but they did tend a bit too sweet overall for our taste, so we started just asking for one of each of the ice creams/sorbets included with the various deserts and it wasn't a problem. Smoked chocolate ice cream, mmm.