If it's not leaking now, then chances are good it won't leak by just replacing the filter.
There is several feet of the double sided foam that helps reduce vibration. If anything have some good super glue type adhesive around. If you accidentally pull that foam tape off, just re-attach. I've changed mine out several times with no problems whatsoever, and I live down in Florida where the skies will just open up on ya.
Are you sure you're not leaking? Make sure to pull the carpet back, make sure there is no mold/mildew. This could be the source of your allergy attacks. Just because you don't feel water on the carpet doesn't mean there isn't water beneath the carpet in the sound deadening material.
If you're not leaking, well good, but replacing the cabin air filter won't make it leak. I recommend, as preventive maintenance, go ahead and seal the base of the filter housing and install the rain hat extension. The full tsb is in the first link. However, if you do find there is water, mold or mildew under the carpet, then read through both threads, removed and clean the carpet, and seal everything mentioned in both of the threads.
Yeah! I think if it is ensured that it is not leaking it is safer now. Since summer is coming better ensure car maintenance. Vacation goes hand in hand with summer time. Ensure you do look after your automobile from winter injury, before you begin your summer traveling. More or less, you want to give your vehicle a rapid once over. In short you want to check your radiator, belts, batteries, tires, wipers, breaks, and much more. Maintaining your vehicle in good condition may prevent hardships later at terrible times. Believe me the $20 belt change now is much better than the $200 tow job later on.
I really don't understand your question but I replace the A/C cabin filter on my 'o2 Vulcan at least once a year. I'm careful to clean out the housing if necessary and insert the new filter carefully to not disturb the gasket. The old filter is always dirty enough to discard.