I think most would agree that you shouldn't fly alone. If so, then the ideal amount of folks present for a maiden would be 2. In fact, new models are maidened at club fields in front of a handfull [or more] of flyers everyday. The right way to handle this scenario is to inform everyone present that this will be the first flight and to also wait until there is a time available to be the only plane in the air.
I agree that 10 minutes before the official start of the big event while dozens of folks are milling around tending to their own business is no time to be checking out a model large enough to do harm.