Yes, I have seen it, and shareware is a good way of getting
around copyright infringing. It gives the user the option of
donating something to keep the program in existance, rather
than becoming and actual charge for continued use. Does the
program cease to function after the trial period? If so,
then the creator is requiring payment, making the product
commercial. If not, then it is up to the user whether he/she
wishes to donate funds to continue development. There is a
very great difference between a request for funds and a
demand for them.