This is where I would have to disagree.

If any air gets in to the engine via the carb slide, you have a bad slide or a warped housing. Boots are not sealers for air leaks or are they sealed from the factory brand new. Oil from the fuel keeps the slide lubed and "for the most part sealed" in the slide bushing. Any debris that gets on the slide could effect the slide bushing resulting in a leak. Boots are only on there to keep debris out as you mentioned and I agree.