I fully agree with Vanessa, and we always migrate onto a schema in which Editor Tracking is disabled. We usually map the source last updated user and date to the creation user and date of the target. After migration we enable Editor Tracking again. (When requested by the client, we also map and migrate the source creation user and date to two additional fields in the target schema: not under Editor Tracking.
Another consideration to keep in mind is that when running Update Subnetwork some features will undergo edits and their update user and date would be set accordingly. Therefore, when you look at the data at a later time, you would not be able to differentiate whether the editor in the last user field was someone making an explicit edit to the feature or running Update Subnetwork.
If this was a concern, you could add two more "update-by-when" fields to your schema and add functionality to manage their values based on specific requirements.
