This may seem the wrong way around, and to some extent, it shouldn’t be this way. However, every time someone new joins a meeting, the purpose of the meeting changes slightly to accommodate their “needs”; whether felt needs or real needs.
Why? Because the people in the meeting are expecting to get something out of the meeting. Or they are expecting to contribute something to the meeting.
So, even though YOU might have a reason for calling your meeting, the people you call will bring their own expectations.
The point is, if having that person in the room is going to change the purpose of the meeting dramatically, better not to invite them in the first place. In the end, it’s your meeting.