I don't know if it is tampering just based on what Allen allegedly said.
I suspect in a lot of cases, a player thinking of entering the transfer portal talks to their AAU coach, or HS coach, and tell them this. Asks if they can help gauge interest, and maybe provides a few schools.
If an AAU coach or HS coach contacts a member of the SU staff in this kind of a circumstance, I don't think this is tampering. Even if the member of the staff takes the info back to the HC and rest of the staff and they discuss interest in a potential transfer, I don't think this is tampering. And I think it is fine if after that meeting, the staff member gets back to the coach and lets them know if Syracuse would or would not be interested.
All of that seems fine to me. I would think this is what the NCAA would actually want. If you want players to have true freedom to transfer, I think it is reasonable to allow them to casually 'test the waters' and see if putting your name in the portal is going to be worthwhile. Especially given once you put your name in the portal, it appears your scholarship is no longer guaranteed.
I think when the school contacts the player, or people close to the player and expresses interest, then you have tampering.