We have the devs of all but one of the alternative UI's on our discord server. We try to provide options for our users as well as give some extra exposure to the Lemmy developers community by hosting these on LW. It's actually pretty cool to see that devs from different apps are going through each other's code and are being helpful. And other community members are actively helping the developers test (and request) new features.
So that is one of the things that we did to "play safe". But I understand your concern and I'll have a talk with the team how we can organise something like a code review of the UI's we host.
We have one more UI to be announced soon. And that will most likely be the last one we will add.