Role of Fermi's Paradox
If there are bad guys out there that will do us wrong if and when they can find us, then we're pretty much dead meat. But if we can avoid detection for an extra century or two, why not survive a little longer. Our leaking signals are less detectable than blasting an high-power signal though, so not blasting our presence might buy some time.
I said earlier though that it doesn't matter much, and my reason for that is Fermi's Paradox. Since aliens aren't here, they're either not out there, or they're out there but not very interested in overrunning us.
On the off-chance that some aliens would do us harm but are kept in check by others, I still say we should keep quiet and not test the system's safeguards.