That doesnt make any difference. If I'm using my work laptop at home and I buy a game I can play it on my work laptop. I may not own the laptop but that doesnt mean I cant install the game on my laptop.
EDIT:
worst case, he installed posiedon on more then one Amiga..his development machine @ Elbox and the one he demo'd it on. Ok, delete the one you had it installed on and just leave on one machine. No harm no foul.