What's rude (and can escalate to being worse than rude) is when people try to goad others into showing them, or become angry and insulting when they get refusals. This happens enough that many of us try to discourage people from asking in the first place.
I see no upside at all in showing my affiliate sites to the competition, and I know from hard experience that there is a big downside. So, I don't do it.
, unless you have a really robust system, 300-500 merchants is way too many! Your poor server, trying to handle all those datafeeds! Do you have a dedicated server? I haven't seen a shared host that could even handle the size of a ZIPPED CJ
feed with ~70 merchants, much less actually RUN a feed-driven megamall.
And if you're thinking of just listing the merchants by name, with no other info...don't bother. Link farms don't convert worth a darn. It's better to have a minimall with 5 or 10 merchants that actually shows some products and tells something about them, than a megamall that's nothing but a ginormous names-only link farm.