atthisstage, no I do not think it is ethical for the client to do this. Here's why: they are risking someone else's property (the software company) by assuming that I will do the ethical thing and delete the program when I'm done. I don't think they have the right to make that assumption and take that risk with someone else's property. Now, if THEY were the developer of the software, then it would be OK for them to take that risk. In any case, if it were me doing the modeling work, I would not "borrow" the program to do the work, because I would have to assume that the person who was "loaning" me the program was the legitimate licensee, and, again, I have no right to make that assumption. The "loaner" might actually be loaning me pirated software.