I picked up a nail as I was pulling into the farm last spring and went ahead and set up anyhow.
I purchased one of those ramps and used it a month later as I was leaving to put the spare on. I plugged the hole just to keep Murphy at bay on the ride back. Went to the tire shop and replaced all four and put the spare back in its place.
The ramp worked just fine for me. The only thing I noticed was that it wanted to settle into the ground a little. If the ground is soft place a small piece of plywood to spread out the weight. Settling should not be a problem on a roadway or inn a campground.
I never occurred to me I could do the same thing with lynx blocks.