I've read on here the bartenders aren't allowed to make/fill drinks up in them, but you can order a drink and pour it in there. for this reason, we will be bringing our tervis cups when we visit in may.
The bartenders are not allowed to fill them and it would really not be very nice to put them in a difficult position by asking them to do so.
Having said that, we always take our insulated cups with us because we like how they keep the drinks cold and the sand out and we use them every day but we don't ever ask the bartender to fill them because we know they are not allowed to do so. I will get a drink and pour it into the mug myself if I am taking it to the beach with me. I still get the benefit of my Tervis Tumbler and I don't create an awkward situation for the bartender.
Forget the Bubba's. We brought them first year and never used them at CSA. The bars are so close you can get a refreshed drink within minutes. Also, there is the red-flag service. Just raise the flag and soon someone will stop by to take your order and bring it to you.
If you do take your Bubbas, do not expect the bartenders to fill them, just ask for two of what you are drinking and pour them in yourself. We did this last year and did not bother anyone in our group. The bartenders are great and we did not want to cause them any issues with management.
If your inclined, just get a tray of drinks and take out into the water and serve everyone around you, just make sure you return the tray and cups, its a great way to meet others.