On Monday, August 7, 2017 at 5:12:19 PM UTC-5, Tom BravoMike wrote:
Is there a minimum altitude they are allowed to release at, or is it
about a distance from the start or an area assigned for release?
Anybody knows in this specific case and competition?

In many/most competition rules release must be at a specified altitude.
Reason being if you get off early (even in great lift), you're now
a traffic hazard in the (for large contests very dense) towing pattern.
When the towing is done properly and everyone delivered into a
thermal just at release altitude, the traffic hazard is greatly reduced.
In a contest with 100 gliders this is a big deal! And even with 30...

Hope that helps,
Best Regards, Dave