That was what mozilla did when they had resources to do so... now I think they have a different tactic but if you obfuscate it they require a full unadulterated source code link. google operate(d/s?) on the permissive model where you pay for a small membership and then they let you put it up unrestricted and if it gets too many reports it gets pulled. I think mozilla has the slight edge personally but either way i'd be wary of installing extensions willy nilly.
Yeah it's kinda a big dichotomy though... they only review very few extensions after doing their automated testing on them. my extension is marked as unverified and there doesn't seem to be a way to change that other than getting some unknown critical mass of users where they are interested in doing a manual review. oh well... not a big deal I guess and the extension is more for my own usefulness.