A trophy for won events would prolly be exploited alot, two players starting "fake" events, one as event holder, the other as winner, simply to get some kind of item to put in their apartments.
Making it so a trophy cost some amount of ped would be like making furniture available in the trade terminals. Ppl would still make fake events to be able to buy that trophy.
A possible event terminal would be flooded with events just to get a trophy
Maybe making a restriction so only events with atleast 50 contestants would be able to get a trophy for the winner.
/Edit....
Making events terminals where event holders could add their event, when the event is added to the terminal it would be in a "Pending" state until enough players have joined that event, when enough have joined, let's say minimum 25 players, the event would be moved to a "Confirmed" category, fee for joining an event could be 1 ped minimum or so, paying for the tools provided by
MA and a possible trophy.
The fee for joining could be adjustable by the event holder, so 1 ped went to the event terminal, and the rest for winning prizes.