The ego battery is sealed at the terminal, so
juice will not get in it. However, if the leaking is severe, and the button becomes soaked, it COULD cause some problems there, but this has never happened to me, and I've had lots of messy leaks with my ego.
A drip shield will certainly help. I also find that thicker juices are better for dripping, so I have some drip-only VG juices I make for just this purpose. Cartos like thin, but thin will tend to leak more with dripping into attys. If you don't make your own juices, I would recommend VaporGalaxy.com for unthinned drip-juices. The tiramisu and french toast are excellent!
I do 3-4 drops DIRECTLY onto the atty bridge. generally anything in
vaping that you over fill will leak. Gurgles will tell you if it is about to leak. I also drip into a Boge LR 510 carto...in fact that is my main vape now, with an ego or kgo battery. I use a drip tip, preferring the wider metallic ones. In fact, since I started using these, I have barely used an atty. This way is also quite good with dual-coil cartos. Just gotta remember to not get
juice into the center hole much, as cartos will also leak.
Good luck!