Please no. We don't need a reason for people to roll around looking for people standing at ATMs who can't defend themselves.
This game doesn't need more monetary penalties. I got sniped last night while out in the desert seconds after spawning into free roam because I was in my phone menu depositing my winnings from a race I'd just completed. $2,000 gone. That's not a lot in the grand scheme, but half of what I'd taken in that race.
That's fine and I understand why people don't want to lose their money. They might as well just remove them from the game. They serve no purpose other than to trick people who don't know any better that that's the only way to deposit cash. If there's no incentive to use them over the obviously better option, then there's no point in having them.
That being said, your situation wouldn't have turned out any different either way, as you said you were sniped in a desert trying to deposit your winnings.