So Appointments would be safe, especially if you import them from a spreadsheet. Then you can set the status in advance to completed so it won't be active.
Alternately, you could create a custom activity entity type of "Event Interaction" or the like. By doing this, you can segregate out event notes from actual appointments when you do reporting if needed. It might also help you do things
like help demonstrate where your business is coming from.
[EDIT] One thing that just occurred to me, you could make a Campaign for each event and then use the Campaign Response for each person talked to. That might also work, especially if you want to have better reporting on lead/sales sources.
The postings on this site are solely my own and do not represent or constitute Hitachi Solutions' positions, views, strategies or opinions.