I agree.
Let's face it, there's an unwritten rule that experienced players tend not to target each other, making it unfair for new players. The update to revenge killing has helped to prevent this 'targeting' and made the server much fairer for newbies/solo players, but the same type of update is needed for the usage of /rob.
Many experienced players do this, especially in groups when they heavily outnumber others, making new players want to quit. If a new player quits, they're likely to never return. As much as I personally would not like this if it were implemented, for the good of the server (increasing the player base) there should be a limit of at LEAST 12-24 hours game time (12-24 minutes IRL).
I remember being a new player and having groups of players come up to me and /rob turn by turn. The effort was laughable but over time it just felt like bullying, making it feel pointless earning money if it's going to get robbed anyway.
Put all of your money in the bank to avoid being robbed. It's as simple as that, there's no need for a rule.
If I earned over 20m after this update, I'd never log in again as it's very unfair for players that earned a lot of money before the tax update, for example, I don't see this lovely player around much anymore:
pop smoke