I do think the term "affiliation" is vague and ambigous here. It may refers to at least five things:
How a person "belongs to" (or works at) an organization - This is the original scope of the property
A (independent) club or society that contains member of another organization - if limited to schools, this is the proposal. There're also other clubs dedicating to employees of companies or other organization, but most of them are not notable.
I propose that we should limit the property for the first use case, and use different property for other use cases.--GZWDer (talk) 19:25, 13 February 2019 (UTC)
I don't think affiliation (P1416) is necessarily limited to (1). Some clubs are affiliated in various ways with other organizations without being (4) or member of (P463). I'm not sure if the currently proposed English label covers all of (2). For some, the link is primarily the location even if they may participate in some collaboration with the affiliated entity. That the organization is a student organization can be added in P31. --- Jura 16:35, 15 February 2019 (UTC)