I think you are right about the food truck being a signal. I also think that PHS has sent so many hints. I thought of something encouraging for us shippers...a little deeper dive into the HK fan meeting response to the Valentine’s question. Did you notice his body language when the question was asked. It is very protective—arms crossed—his chest covered and he appears to be trying to think of an honest response that still protects his privacy.
However, as soon as the fan yells out PBY’s name, he throws his arms out and his head back—completely open. This is his honest answer to the “question.” Then his expression changes to teasing and his vocalics and gestures jokingly say “I want to spend it with all of you.” Haha. But he has his inside joke face on. He is able to be honest and yet give lip service to make everyone happy.
If if there was nothing between he and PBY, then the automatic gesture is to shake your hand no, even as you laugh. But he didn’t do that. And respect for her, if they weren’t dating would seem to dictate this. This to me was a big clue——reading the nonverbals.