Sprint: Practice swim or no? (Page 2)

It's good reading stuff like this.  This week, I honestly started feeling smoother and faster once I hit 500yds.  It has not made sense to me but that's how it felt.

After having an all-out OWS freakout during my first race, I find that getting into the water ahead of time helps me get used to the temperature, seaweed, water clarity, chop, etc. so that none of these things come as a shock when the race begins. Warming up the muscles is important, but for me, the psychological component is more important.

It takes me forever to warm up swimming.  I need a minimum 400 yards before I even feel human in the water.  Last sprint I did I swam the entire course to warm up and PR'd for 1/2 mi. swim time.  Of course everyone is different. 

Is it always possible to get in the water before the race start? I mean...is it ever not allowed? Just wondering because for my next tri coming up the swim will be in a fishing lake which does not allow swimming except for the triathlon. I wanted to swim in ahead of time, as in before race day, but it isn't possible. I would love to be able to jump in a warm up though on the day. Has anyone ever been forbidden from getting in to swim around before the start?