Not all vinyl floors have the same surfaces. Some are made of urethanes, some pvc. What is becoming more likely is that newer rvs have products that are not adhered and allowed to flex with structural movement and temperature changes. That takes away the possibility of adhesive discoloration bleeding through the surface.
We've seen room numbers in doorways and locations of sprinkler heads show up through rubber flooring in hospitals.
I think most mats these days will have warnings or guarantees not to stain. FWIW...French's mustard left on your floor and you will be looking for a mat. Now I want to go camping!