Yea verily, MrHub, I didn't have an issue parking at the Poly in Feb or in April, but having an honest face goes a long way.
Generally, the process for parking at any resort, even the one you're staying at, is the same. Show the guard your parking permit and a resort ID. Be forthcoming, don't be a jerk, and let security do their thing. I can't say I am always truthful IF I am asked why I am coming to a resort. Admittedly, sometimes I will park at the Poly to expedite a quick visit to the MK while telling the guard that I'm going to dinner or meeting someone in the bar. But for the most part, I just tell the guard I want to look around. Often they will ask me to park in the boonies, which is OK with me.
Having a parking permit and a resort ID sort of means you're a member of the club, you know the secret hand shake and the password. Security is only looking out to be sure you're not going to cause trouble and, if parking is very full, take up a space that a legit guest should have.
From a Disney perspective, I think they want you to visit the other resorts in the hopes you'll spend even more money the next time you come to WDW. But at the same time I think Disney merchandising has shot themselves in the foot by eliminating most of the resort specific stuff in the gift shops.
Go visit the resorts. It's part of the magic.