my3dogs, when we bought the home, they had stair runners over carpetted stairs and stapled. We removed them before we moved in because they were dirty. They were adding thickness but we never walked on it so we do not know how much hazard they were. You might be right. May be just vinyl to protect the rug. My kid is super active and she spills all over and won't stop.

My kid is super active and she spills all over and won't stop.

Can you limit where she goes with drinks and/or food? To me that seems like the logical solution. Any kind of runner on top of carpeted stairs presents a safety hazard.

It is actually my H's choice and he is hell bent on putting rugs on stairs. He does not like vinyl rugs. So in that case, what kind of rugs should go?

This sounds very dangerous regardless of whose choice it is.

I doubt any carpet and rug installer will agree to install a rug runner over the existing carpet. The liability when someone falls down is too great. The cost of installing rug over carpet would be as high or almost as high as replacing the carpet in a few years.

Why don't you just recarpet the stairs in a durable tweed that doesn't show spills.