Our field data collectors will be going to different locations and if there is a locked gate or otherwise no way to collect data at that location, there is a field for "no measurement" which will be filled in through the domain code "NM". I want to block erroneous entries in some of the other fields. How do I set this up and where? In my map before sharing as a feature service or in Collector data table? Is this even possible?
I don't think this is possible to achieve in Collector. It does not support field calculations or other field dependencies the above scenario implies.
On the other hand, you could do all this just fine in Survey123, as it supports field calculations, hide/show questions based on other question(s). Bear in mind that Survey123 can only collect points for now.
I hope this helps.
I would recommend Survey123 for such things. However there could be one way to solve that in Collector.
In Arcgis Pro you could work with subtypes. If you create one subtype called Type and include the type "NM" and in that case use other domains for the fields you don´t want to populate and other defaults.