I would suggest taking the bottle off of the mod and capping it to best prevent potential leaks.
I've had security ask about the
juice with a suspicious eye and caution me about "unknown liquids" on board, so I've taken to taking the bottle off and storing it in my liquids baggie. For some reason, that doesn't raise the same issues.
Also, note that all spare batteries need to be short protected (stored in safety case that prevents accidental metal contact with the terminals) whether carried on board or in checked luggage.
You might also get a keener who asks to inspect the device. It does look like a detonator switch, but I've always been able to explain what it is and does to their satisfaction - they just haven't seen them before, in most cases. One chap wanted the reo web site address to check out for himself

.
I've taken these things to 4 continents - never had a leak issue (with the bottle precaution above), never had anything confiscated.