Doubling security deposit for high risk people

[Bienes Raices]

I've been reading another forum and they recommend charging twice the security deposit if the FICO score(s) is below 600. Has anyone tried this and if so were the people willing to pay?

Also I was wondering how people here deal with "self-employed" income--do you increase the deposit for that, or just refuse to count that money as income? My concern is that it's harder to gauge, since you're relying on the applicant to provide tax records, etc,, which could be doctored.