I've never been in TTL, but I plan to do the OW swims Thurs and Fri morning on race week. You know if you have a hankering to jump in TTL you can come swim too. I don't believe you have to be registered. I know a guy who's from nor cal that's coming down just to swim. He's going to be here on business so he's taking advantage of the OW opportunity.
My plan is to try the sleeveless wetsuit thurs am and if that doesn't work to break out the big daddy sleeved suit on Fri. May even jump in saturday morning just to get an even better feeling for the water.
I used to surf so OW doesn't freak me out. It's just the cold. I hate cold!