Ummm... do you not know that for at least the last 5 or more years, many mazes have been open as early as 5pm? When they say it opens at 7pm, that's when all mazes are open. This year, 8 mazes out of 10 are open before 7pm. Early Entry. They let haunt guests in as early as 5:30 so they can be in line for the early entry mazes as 6.
So no, you don't have to wait until 7. In fact, as I stated above, because I was taking advantage of Early Entry, I haven't seen the Scaremony in years, and on occasion it has, in fact, blocked me from getting to other mazes. I wasn't as upset about that as others, but I can see how others would be.