The first thing I learned way back when was that there are no rules. So technically a cache hider can claim their hide if they want to.
But, as a practice it is generally frowned upon and not encouraged. There are several different threads on the GC.Com forums that address the very issue.
I think the best way to deal with it is to speak to the cacher (who by the way is kind of not far from just starting out) and a simple explanation or discussion would bring about an understanding of accepted practices and while this practice is not "Wrong", it is not a common practice.
Thats my 2cents worth on this one.
I'd really rather not cache, but I am helpless in the grip of my compulsion!