Multiple Flaws

Apologies if this has been covered already, but a question:

How do "multiple flaws" work as augments? I'd assume that one can only have *one* mundane flaw apply as a negative augment at a time (just like only one mundane ability can positively augment).

Curious, because I've toyed with giving rewards for taking flaws, but a player could abuse it by taking overlapping flaws (clumsy, weak, etc.), but only need
worry about *one* flaw at a time.

Cheers,

James