No, I don't think that you did anything wrong by 
responding to offers. We're all human in that we 
want to share our love and joy of this hobby with 
others and when people say and do the right 
things, we want to believe that they're sincere. 
The only way that you can avoid this situation in 
the future would be to plainly state on your 
gallery that all offers would be deleted and not 
responded to. This won't mean that you won't get 
any more offers, but at least you can delete them 
with a clear conscience.
Here's a link with to this topic, which you may 
have already seen:

http://pub20.ezboard.com/fanimecelspersonalcollect
ions.showMessage?topicID=34.topic

These ladies have certainly impressed me with 
their intelligent and thoughtful posts.

BTW, are you the same Kathleen with "The Many 
Moods of Ryoko" gallery?