I could see myself doing that. If just to remove the monetary motivator and see what they actually want to do. Thing is that I don't think they could do much to unbalance the game with it. Buying magic items IMC would be an adventure in itself as they would have to probably pay off people to be introduced to the people who would make or sell such things. By time they traveled to the city where items could be purchased, paid for their lodgings (and most PCs like to go in style and probably would have to in order to impress those they're seeking to befriend), spread a little money around to get the proper appointments, deal with people who can provide such items and then probably pay more than suggested retail price for them, it would be an adventure arc all unto itself. It would flavor the campaign as they would begin to gain access and contacts they normally wouldn't get till several levels later but don't think it would disrupt the campaign. There there's that if the flashed too much money and it was kown they were low level, they would become targets for rogues and such. For that matter, how could it disrupt the campaign if the players and DM are having fun?
I did have something like this happen to me before. At a low level the Dm gave us a really powerful sword that he was sure that we would keep. However, due to what was supposed to be flavor plot where our small kingdom was taken over by barbarians and that we couldn't come up with a good way to split what the sword was worth among the party, the paladin demanded we sell the sword and use the huge amount of money (and somI minor magic items) to hire a merc army and free our kingdom, which we did. It threw the DM for a loop but he went with it and it all worked out. We freed our kingdom, received some minor noble titles and land with a small "haunted" keep that we had to go clear out whch became our base of operations.