So, on the majority of cruise servers, there is a system that deals with money, either gain it by driving, steal, or having it sent to you. I was thinking, what if all the money you had from different cruise servers was put on to your username and used on any server? Like you have €5,000 on one server and €470,000 on another, your total would be €475,000 (it would be in Euros, of course, since the majority of cruise servers already are). It wouldn't be limited to cruise servers, though, such as winning pots from race servers. For 25 or more racers, you could win €10,000 for 1st, €5,000 for second, etc, but for small races, like 4 or 5 racers, it could be more like €1,000 for 1st and €500 for second. Entry fees for tournements could also be a posibility.
To avoid cheating, refunding would have to be done away with or stay local to the server (i.e. if an admin refunds themself €100,000, the server money would be €575,000 but the universal total would still be €475,000).
Also, you would have the money from cruise servers you haven't joined yet. As soon as you join the server, the starting cash gets added to your total (i.e. if a server has a €4,000 starting total, you would add it to your universal total, €475,000 + €4,000 = €479,000)