Since the 3 hose clamps used on my snorkel clamp on to relatively thick and soft material, I didn't feel it necessary to use a sealant. If clamping on a hard, non compliant surface like an aluminum tube, then I would have. For example - I installed my own sprinkler system and used screw type hose clamps on all the fittings but the 1" poly hose is so thin that the hose clamps didn't seal well and many of them leak, not enough to matter but some do leak. Remember that the stock filter is backing up anything that gets through a snorkel system, mine was spotless at 1137 miles living behind the 3" Uni pod filter and I let the Uni get filthy before I cleaned it. 😊 That snorkel idea is linked in my sig, copied directly from HondaBob's idea for those that haven't seen it.
1137 miles, all with the Uni on a snorkel behind the passenger seat -