So the time has come for me to start planning DS's 1st birthday!!!!

I have chosen a park, but the problem is I don't want to have the party til 2pm.. I have booked the park, but it's still a public area, so a table technically isn't booked.. So should I risk hoping that that there will be a table available, or could I kindly ask people to move along? or make it early in the morning? DS's sleeps in the morning though, so it really isn't the best time.. WWYD?