My sister is going to be flying through SEA on Saturday with a 3 hour layover from BOS. I live in Seattle and would love to catch up with her for a couple hours if possible. I am a Lounge member, so I could bring her in with me if I were there.
What are my options to get airside and enjoy the lounge with her? Could I buy an AS flight for Saturday night, check in to get the boarding pass, and then cancel with funds going to my wallet after I enjoy the lounge? I have plenty of flights to still buy later this year, so I know I'll use it. Can I cancel a flight after check in?
Or do I try and find a super cheap flight on any airline for Saturday and then just throw it away?

Would love any suggestions.