I'd still be careful. Early mat conditions can be questionable. Hook a carbide and you'll take a big drink.
I don't understand this statement. The mat is only put down once, they do not add snow to it during the winter and little to no natural snow falls down there, so it's condition does not change. Grooming has been done to it now, just as it is all winter. Plus, there are guardrails on the edges of the lower bridge deck, because in the summer it is the road surface that cars and trucks use. It would be an enormous trick to get over those guardrails, mat or no mat.
-John