That is the limit for several reasons.
Carriages aren't designed to carry more than 6 passengers. Don't believe me? Ask the company that had carriages break in half from the weight stress. They are Amish built, and not for mass transportation. If you want to ride with your entire group we have gone to great lengths to have a vehicle to suit your needs. We also offer an 8 to 10 passenger wagonette and a 12 passenger wagon, or you may opt for multiple carriages.
Licensing and insurance also dictates the passenger limits. NUFF SAID THERE!!

If those reasons aren't enough for you....
We treat out horses humanely; they do the hard work. These horses are athletes, a part of our heritage, and a part of our family. They deserve respect for the work that they do. So PLEASE don't ask us to hurt or overwork them.