In my experience the first year of PISE (when a fellowship was not mandatory) there were quite a few students in PISE that did not know the EA basics or that were not EA aligned. This lead to some difficulties in the organization of events in terms of the organizers being EA aligned and it made it difficult to determine how in-depth events could be. Therefore, I would still recommend a mandatory fellowship to starting groups (that have a member structure) in places where EA is not well known yet. I think I would prefer a situation of only having a few members that understand EA and are aligned above having a lot of members that do not understand EA well. However, I would start doing this as part of a recruitment round at the beginning of the year (not the end) when people still have the time. I do get that this might lead to potentially missing very promising members that just don't have the time. To mitigate this, I think you could tell people to contact you if a fellowship does not work for them but are really interested in joining. That way you could come to a solution together. For example, if someone is really motivated to research EA on their own or go through the fellowship manual in there own time, I think they could still join.
Additionally, students at PISE that could not join a fellowship, were not motivated to research EA on their own, and did not have EA knowledge already (and thus could not become a member) could still join events that do not require previous EA knowledge. This way they can still get more intro knowledge about EA which might motivate them to join a fellowship or research EA more in their own time. I don't think you should be exclusive to members in all events you organize. However, to guard event quality (if you start working with the same "committee" structure of most Dutch universities and not just have the board organize events) and stimulate knowledge gain of members, I do think "committee members" or members attending in-depth discussion evenings should have previous EA knowledge through a fellowship or there own research.
I hope that answers your question.
Thank you for your suggestion! I think that would be a very good idea. We had tried reaching out to the career centre last year when we ran the fellowship, but were not able to advertise it there as our group is not recognized by the university yet (at our university a group has to exist three years and fulfill certain requirements in order to be recognized by our university). However, I will note this down for the board of next year to do after our group is recognized by the university.