A generated UUID can make mock data structurally realistic. Label it as a sample, pair it with obviously fake names and addresses, and keep only fields needed to demonstrate the behavior. Do not copy production IDs merely because they already have the right shape.
Use the UUID generator to create test identifiers, but do not treat a UUID as an access-control secret. A standards-compliant random UUID makes accidental collision very unlikely; where uniqueness is critical, enforce it with a database constraint and handle the rare collision path.
If the example is published, someone should immediately see that it is synthetic.
Akousa