+1 to FromZwolle...
A keg shouldn't leak once it's sealed up and pressurized. Did you check to make sure the lid o-ring was seated fully? How about the posts where the beer and gas disconnects go? Is your beer line sealing right?
I'd say it's time to trace down that leak and fix it up ASAP. Otherwise, you're just pissing out CO2, and beer, from the keg.
BTW, the ONLY brew you should have in the fridge, that's not in kegs, comes from the picnic facuets/taps when you put them back in, and you've not gotten every lick of brew from the end. So maybe a couple of drops per time you pull a pint/glass from the keg...