DYKWIA at SkyPriorty Check-in at DTW today while I was checking a bag. This lady walks up the exit lane and just stands there. Agent who was assisting me then asks her what she’s doing there. Lady says she’s Platinum, Business Class. Agent says “the line is over there. You’re in the exit line”. Lady insists she is in the right spot and was told to go there, despite a line of a few people where the line should be (is). Lady refuses to move or go to the correct line. Even says “well those people came in after me so I’ll just wit here and then go to the next agent”. When that didn’t work out after a couple minutes the lady walked off and I thought she was heading into the correct spot for line but then a minute or two later when I finished up and and left, she speedwalked back up the exit line right to the agent who had just assisted me (and cutoff a couple who walking up to the agent from the correct line).