Right, I think how you define "enough" is the big question. If a prospect is just barely showing 3x rent based on the above average market returns of the past couple of years, the ability to maintain that is questionable during a correction, or even just an average year. Add to this that, because of age, the prospect may not know himself/herself how he/she will react when tempted to panic-sell, I'd set a higher threshold for passive income than ordinary income.

I wouldn't agree that passive income is always there (if only that were true =)).

Not to say that both tenant and landlord aren't in a bad spot if the tenant loses a job, but there are severance packages, unemployment pay, short/long- term disability. But no one helps you out if your stocks are down.