You have to evaluate ramps. From an engineering perspective some are sound but many less so. On some models if one rivet in the rod on the side lets go you could get a ramp collapse. Rhino ramps I am unfamiliar with.

Old mercedes diesels may have more weight on the front wheels than many other modern cars perhaps as well should be kept in mind. Common sense should be used in all cases of elevating cars and getting under them.

I always position support blocks of wood as a safety no matter what form of elevation I choose. Personally I would never use some forms of cheap ramps alone as the principal support.

Two by twelves of different lengths of wood nailed together are one pretty secure approach for ramps althougth they would be heavy. They absolutly would not collapse.

The common sense has to play a part as well. Never elevate a car to get under it where it can be hit by another car. Do not elevate cars on grades unless extreme precautions are used. Do not get underneath and apply extreme torque to a fastening. Unless you make absolutely sure the car can not topple. I only go under a car when I feel both comforatable and it in my mind it is absolutely safe to do so.