The penalty for having a party on an off-limit area might be grounds for a penalty such as early termination of rental agreement or any number of things.
You need to review your lease agreement and/or speak to an attorney.
Your best bet is to consult an attorney. I would think if anything were to happen on the roof you would be criminally liable, since you knew the roof was off-limits. However, I am not an attorney or a law enforcement officer.
My advice would be to heed the restriction and stay off the roof.
Chad Gray PA, Realtor
Luxury Living Fort Lauderdale
(at Coldwell Banker Residential Real Estate)
100% of clients rated our service as "EXCELLENT"!