Mention gap year plan or not?

I already know that I will want to take a gap year before starting college (I plan to apply to college during senior year anyway), and I intend to spend at least a good part of that year working on a humanitarian project in a field that I care deeply about and that will be strongly emphasized throughout my application. When I write my college apps (next year), assuming I am still committed to these plans, would it be a good or bad idea to mention my gap year plan in my initial application (as opposed to leaving it out initially and then proposing it after I commit to a college, which from what I’ve heard seems to be the standard method)? Including it seems like it would help legitimize my aspirations in the field, but I’m just concerned that top colleges might be hesitant to admit me under the premise of definitely taking a year off (especially given that these day each successive incoming class seems to be increasingly selective). Would I like be rescinded then if I didn’t follow through with those plans? It just seems like there’s probably a good reason I’ve never heard of anyone doing this, despite knowing so many people who seem to know exactly what they want to do years ahead. Has anyone tried doing this and would or would not recommend? Any input would be appreciated, thanks

bump

I would not.