To be honestly blunt (though hopefully not offensive), common sense suggests that anything filled with liquid should be carried in such a way as to stay the right side up unless there is a dire set of circumstances present.
I honestly wouldn't trust any CE2 or similar design flopping around loosely in my pocket. From what I hear, folks who do that often end up with wet pockets.
Being female, I'm used to carrying such things as, say, perfume bottles, the spillage of which is much, much worse than e-juice, because it tends to drive anyone within ten feet of you to running away and screaming (picture skunk).
You carry such things in a pocketbook in a zipped up compartment (preferably a moderately liquid-resistant one), and generally leave your pocketbook in a more or less upright position. If it's flopping around in the main part, you are asking for wet wallets and screaming bus neighbors.
For a PV one can use a whole number of things - a lanyard, a case in a pocketbook, a small breast pocket, a pouch on a belt clip, etc. Pants pocket is just asking for trouble.