Larry N. said:
Perhaps it's because of the unfamiliarity with a potential safety problem if it's not done right. Those "few" miles could be a killer if mishandled, but are no big deal if you're a veteran of doing this (but you still don't dare be careless). Flying a Cub around the pattern is no big deal to me, but could be a killer to someone who's only experience is with a simulation on a PC.
It's definitely worth being sufficiently concerned to learn how to do it right, and some folks HAVE died over the years from not doing it right. Not everyone is an instant expert.