So, how many people actually do a leak test after they instal their snorkel to ensure there are no leaks.
Take the scoop or pre-filter off, start engine, then put hand tightly over inlet.. If sealed properly the engine will choke out and stall.

Those with Rugged Ridge snorkels in particular should do this on a regular basis to make sure you have no leaks in the many connections it has. A good friend had the lower connection come loose and it sucked water into his air box.