Is there a way to prevent users from editing the features while allowing them to edit the related tables?
When you create the feature layer in AGOL, if you only select "only allow editors to add attributes", you won't be able to add any records in the related table in Collector. you will end up selecting " " option, and disable editing for the layer in the webmap you are building, but your webmap won't be recognised by the collector, because you don't have an editable feature layer!!
So what should I do then?
It think it's quite common that you don't want the non-spatial people to mess up your authoritative spatial data while you still allow them to edit their own business data in the related table, is it right?