First thing first, I havent seen any sites that hold withdrawal due to someone that win it from faucet amount. Chances are your account could be flagged as faucet abuser or such.
Faucet is meant as a feature to help to try out a site however most seems to "hope" to be rich by gambling with it. Speaking frankly about faucet, it is one of the unique feature that differentiate each sites and that is one of the significant diffference among all the sites.
Some sites offer huge faucet amount, some offer none while some other offer a stackable faucet amount. Also be aware that there are more faucet lickers than actual gamblers ( even in PrimeDice it seems ) .