Aagh!

So I just found out that...the weekend we scheduled our wedding for is the same weekend as the HUGE car show that is in town every year. I wouldn't be worried, except all of the hotels in our area are known to book up completely while people are in town for the show.  I'm worried that our family won't be able to book rooms if they wait too long.  Now I'm not sure what to do.  Should we change the date? Or barrel on through and book hotel blocks and encourage guests to book as early as possible if they are planning on staying in a hotel. Eek!