Folding Chairs Sinking into the Grass?

Our ceremony is in a small butterfly garden, the garden doesn't have benches or pews built into it so we will have to bring chairs.

So my parents are borrowing chairs from their church to use for seating for the ceremony. They are metal folding chairs with round supports.

My dad brought up the concern of the chairs sinking into the grass and to prevent any sinking, he wants to lay down some plywood over the grass and set the chairs on top of that.

I really don't like the idea of placing plywood just for the sake of not having the chairs sink. I worry setting down the plywood will only damage the grass and honestly, I think it will look trashy.

But is my Dad right to worry about the folding chairs sinking into the grass? I agree they might sink a little, but I don't think we have to worry about anyone not being able to get up out of their chairs.

August here is usually very dry, and even if it rains, we've arranged to move our ceremony indoors, so I really don't think the chairs will have any trouble.

Anyone have a similar issue with chairs sinking into the grass? Was it really that much of a problem or did you wish that you had put more thought into making sure the chairs didn't sink?