Draining races of all their credits still too easy as of .903
The general "drain them dry" philosophy of Drox 1 seem to still apply. Set a race up to alliance then they'll just let you take all their credits with repeated demands, no matter how much they have.
Would recommend a time-out on demands, maybe something like 5 minutes as a nice band-aid.
As a potential "fix" I would just have them declare war (or something like a 1000% penalty from a normal demand) on any follow-up demands.