I was wondering about that. I knew someone who thought it would be cool to go windsurfing in January on St. Clair. He had to walk out about 100 yards on the ice to get to the water, and sailed around for a while. Sunny day, decent breeze - Long board sailing. Had the lake all too himself. Life was good. Then when he tried to come back in. Not so good. He found that the ice had gotten too soft in the sun and he could not get back to shore. The ice broke every time he tried to land. I guess they had to get the coastguard to rescue him.
Getting out is half the battle - you have to be able to get back home too!