I doubt you would be able to crash their events, and it would likely be a good way to make a bad name for yourself.
Sure you could keep the contact details of the person - it would be good to. Not sure how much it would help in the recruiting, as most of that seems to be done by a school team that is mostly made of alum from the school if possible. Therefore, he wouldn't be directly linked to them. That said, no contacts can hurt if managed correctly.
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