Re: very important question
On a personal note, i`ve seen it a few times, and that is i would be very carefull about printing others disigns, even geting the ok from them.
Reason i say this, is a lot of the time, its permission by way of mouth, and say you sell 10.000 tops with this pwersons prints on, he could then think he is missing out and then play the rouge and say he gave you permission for a few, not 1,000`s
I`ve seen this at first hand with a friend, he had a family friend say ok and made a lot with advertising on taxies and such, but then wanted half the money he earned from it, less to say it went to court and he had to pay some money.
Get it in way of writing if possabl, and make sure the designs are his or hers ?
Just remember that a persons best friend is the colour of money