Instead of just gaining or losing money when killing another player the MONEY-STEAL would also remove or add money to the other player.

To do this in 2.0 look like we'll also need access to the playersubject/target - not just the recipient - in MoneyDrop.

I did this in CelticMinstrel@842d657d, which you've already pulled. It's MONEY_STEAL@ instead of MONEY@, and will never put the victim into a negative balance (which means that the killer may gain more money than the victim loses).

Probably but I haven't actually tested it yet :)

In regards to not putting player into the negative - should we also perhaps match the amount given with the amount taken?

Eg. MONEY_STEAL@25, player has $10 therefore only $10 is deducted and only $10 is given to killer.

Should this be closed?

I dunno; I was wondering about that myself. Doing it that way basically makes MONEY_STEAL@x mean "steal up to x".