I can't think of an example out there, and I'm not trying to out a villain, but there is this idea out there that parachurch ministries somewhat bypass the church or exist because of defect and lack in the local church. UCCF may well have fallen into this trap in the past (and present) and where it does we ought to hold our hands up and repent of it. Mission partnerships like a Christian Union provide no alternative to the local church, nor any threat to it - only opportunity and benefit. In view of that trust needs to be the currency of relationship rather than suspicion. Lack of actively worked out love for the local church is both unnecessary, foolish and wrong.
Personally I'm involved in the ministry of UCCF because I love the local church. What I'm aware of is that it's one thing to say I love the local church, and it's another to live that out. Love works in relationships. I can say I love my wife, but I then have to go and love her. The existence of Christian Unions (UCCF Mission Teams) must be utterly integrated into and connected with the local church. Their members must all be committed to involvement in the local church - committing to relationship, service, giving and being a joy to lead. This means breaking the student clique and getting involved in the lives of non-students.
If formal membership is part of how the church is run that would be appropriate, though some churches neither practice membership nor yet have any kind of capacity for membership for a student who may only be around for 30 weeks a year, and may necessarily be a member of a home/sending church for the other 22 weeks.
It's easy for a Christian Union to view the local churches as an ATM to which they can periodically receive prayer and finance from. Local churches love to offer both of these, but it's really only appropriate if the individual members of the Christian Union are well rooted in the church. Church isn't them 'them and they' who can help us, but 'us and we' which we love to be a part of.
I'd go as far as to say that if a leader in a Christian Union is not doing the above they need to repent of that and sort it out immediately. And if they're not prepared to do that they should resign. Likewise, when choosing new CU leaders it would be appropriate for current leaders to make commitment to a local church a non-negotiable qualification.
Love of the church is surely a matter of character and godliness that is not insignificant. It would be wise of those choosing future leaders to ask the leaders of their church whether they would recommend a person for leadership in the Christian Union, and to ask whether there are any other students in their church that should be considered as leaders for the Christian Union. Usually suitable leaders are obvious because they'll be leading in practice long before they're given an official role. Consulting with the local church in the context of existing relationships of trust is a way to love the church.
Jesus loves the church. So do I. And in view of that I'm not sure parachurch is an appropriate label for UCCF. Wikipedia says 'para' means: beside, near, past, beyond or contrary. Partnership makes more sense. A Christian Union is a partnership in which students who belong to local churches together reach students with the gospel, for the glory of God and the good/growth of the local churches.
The Christian Unions are committed to preaching the gospel to students, bringing them to discipleship. It's entirely inappropriate to have any sense of Biblical discipleship that doesn't include membership to the local church. Anyone reached by the Christian Union should join a local church, be discipled, and ideally be released back into campus mission in the context of the Christian Union, for the further good of the church while they are students, remaining for life as members of the local church.