A sure sign is if a DISigner has blanks in their accounts/threads. For example, I have put a lot of the backgrounds that I have used up on my photo bucket account for people to play with. Howerver, there was someone who put a lot of time/effort into their DISigns and put their name accross them so no one but them could personalize it. And then there was someone else who took someones DISign, added their name and said look at the DISign I created. On the other hand, there have been people who posted pictures of their shirts and said this disigned developed the disign and I personalized it and everyone is fine with that. I find it is always polite to ask first, just in case you might step on toes.
& one more thing to add. Sometimes you will see a DISign you absolutely love. You know if give the time you could recreate it. I figure why reinvent the wheel

If the DISign is what I am looking for and it's already done & it's going to be a pain to personalize it as the fonts might not match, I will ask the DISigner to do it for me.
& last but not least, if you see it, copy it and label who the DISigner is. There was a DISigner when this board first opened that made beautiful resort Mickey heads. I have spent hours trying to recreate them and with the help of a few people I have come close. Howerver, they are very time intensive. If I had of been smart I would have asked that DISigner for a copy of all of her resort heads and would have saved myself a lot of grief and work.
So to make a very long story short, it depends, just ask. LOL
Penny