It's not tubes or brushes or whatever your paint program calls them that are illegal, it's the fact that the artwork from which they are made very often belongs to someone else who has not given the tuber permission to use it. Personally I avoid all tubes & brushes/what-have-you that do not have clear terms of use & all permissions listed. No matter how good it looks or how perfect the tube is for my project, if it's in any way "unknown" or "found on the net" I simply do not download it. What with all the lawsuits over copyright infringement & such, it really pays to be safe.