In CRM, when adding an Event, Interaction, Plan, etc. you are able to choose what Site it relates to and, if the user has a default Site on their user account, it will pre-fill the Site based on that while allowing them to edit it.

However, for Constituents, the default site is instead driven by security role site assignment for the user - which is inconsistent and can be confusing - and the Site doesn't show on the Add form. This makes it very difficult when creating a Constituent record to specify or confirm the Site it relates to.