I have the Delta Skymiles Reserve card and will be flying Southwest out of Sky Harbor Airport (PHX) on Friday. I think either now or starting next year people with this card will have a certain number of days each year when they can use Sky Clubs. If that is in effect now, is the limit applied to anytime you're at the airport or is it still only applicable to days when you have a Delta flight within 3 hours of entering the club?

To be clear, I think it might be possible to pay ~$50 per person to get into the club regardless of what airline you're flying to my questions above are about whether you can get into the Sky Club without paying an entry fee.