Stone stairs for ceremony seating

I would arrange chairs. As a guest, even at the most casual wedding, I'm still dressing nicely and wouldn't want to get grass or other stains on my clothes. Also, it may be more difficult for older folks to bend down low enough to sit down or get back up.

I would arrange for chairs as well. In addition to the potential for stains, lower seating that Hannah mentioned, there's no back support and I know myself and a lot of people I know would appreciate/need something to support our back while seated.

Yes, I agree you need chairs. Even some blankets and back support would be better than nothing. As someone with an "invisible" disability these would be very hard for me to sit on/ get up from.