From what I understand, Pitino was letting Mashburn take Ray Allen out to eat that night. Pitino had already met with him and was meeting with him again the next day. He had told Mashburn to tell Ray about the UK experience.
I think Ray Allen overplayed that moment when Pitino "only" waved at Mashburn and Allen. Clearly he was giving Mashburn and Allen space to privately discuss the UK experience. This is the same thing Derek Anderson did for T-Mac when DA took T-Mac to dinner. Pitino used this strategy for plenty of guys. Meet with the player for day one. Let your player host (Mashburn, DA) take the recruit to dinner on day two. Close up with a final meeting in the last hours of the visit.
I know it fits the salty anti-Pitino crowd that thinks Pitino would have intentionally blown off Allen, but that's not reality.
Allen even recently said that UK "rolled out the red carpet" for him on his official visit to Lexington. So how can UK both "roll out the red carpet" and diss him simultaneously?
It's much more likely UK simply didn't prioritize Allen at that point. He was not a top 40 recruit, and Sheppard was about to commit. Pitino was only taking one of them. Had Pitino known Allen would have become the Ray Allen we knew him as at UConn, Pitino would have laid down in traffic for the kid.
Allen felt spurned, but he had his chance.