If you walk up to the pharmacy counter at any Walgreens or CVS, literally the first thing you're going to see is a shelf of decongestants.

I can’t speak for your Walgreens or CVS, but at mine you’ll see a shelf full of phenylephrine-based decongestants only, because the pseudoephedrine-based ones are behind the counter and out of sight.

Lots of pharmacies display cards in the regular decongestant section that you can take up to the counter to get the ID-required OTC pills. It adds an annoying step, but they are hardly out of sight.

Not trying to be condescending, but are you sure you're referring to "behind the pharmacy counter (i.e. where the pharmacist stands)" rather than on the regular shelves? That's where it's prominent—although as someone else noted there are often "see the pharmacist for the real stuff" cards on regular shelves too.

Yes.

you need to provide a government ID. so probably not an option available to illegal aliens (in many states).