If gambling isn't removed, here's another option:
Make it so that if someone with a debt leaves for more than 10 minutes (or whatever the time is to get weapons/money reset), their debt gets subtracted from their bank account.
For example:
I have $-500,000 on me, and $2,000,000 in my bank. I leave the game for an hour. When I come back, I'll have $1,500,000 in my bank, and will spawn with the regular $500.
This would at least get rid of the strategy where you gamble until you have a $1,000,000 debt, quit, and come back in 15 minutes and it's all gone.