When they come back to scrambling, now they judge the rock based on their new abilities. Class 4 rock becomes easy class 3 and class 5.0 to 5.4 becomes class 4. This is fine if they don't share their opinion with others, but that's normally not the case.
Just because they have increased their climbing abilities, which is good , it doesn't mean class 4 rock becomes class 3. There is an obvious danger here. Class 3 rock will always be class 3. It's not dependent on the hiker/climber.
I have always tried to rate the climbs accurately and not on my current climbing ability. I do not want to see anyone get hurt or even get to a move they can't do and turn around and go back to the trailhead.
Well, that's my two cents. Let me know if you agree.