how much trans fluid would a leaky boot leak on a fully topped up transmission? are we talking a couple of drops? or a small puddle?
the boots are there to protect the universals from dirt drops
depends, theres alot of varibles like how big is the split and where bouts on the boot it is etc
first time i lifted my yellow bug up on the jack i got a nice big stream running out 
your most likely to loose it going round bends and over bumps, specially with a baja which would be atleast stock height if not lifted abit
i wouldnt leave it to long as steve said dirt can contaminate your oil
theres debate over which is the best way to mount them
ive seen them split fairly early with the joint facing upwards
last set i put on the old mans i put the joint facing the front and that was 5 years ago and there holding out ok
just dont get cheap ones
Hth
im not sure where the leakis coming from, im trying to pinpoint it.
On a swing axle gearbox
it could be a lot...
the split boots are supposed to be around 1/2 way or 90 degrees from the top or bottom..
doesn't matter front or back
but there is too much flexing of the joint when they are at the top so they don't last long...
then again You would think at the top would be best
seeing its related to oil level in the gearbox....
Also - You shouldn't wait for a leak before you replace them... same as fan belt etc...
LEE