For my knowledge, using RF instruments, the greatest risk is mechanical, rather than electric, namely connector demage.
Look for Agilent (hp) AN "principles of connector care" or similar title. Read carefully and apply practically.
Good connector coupling practice, give to the user a precision method of operation, not found on other books or papers.
The accuracy of every RF & microwave measurement depend strongly on how the connectors and cables are "good".
Also, the ultimate uncertainty, is often related to the transmission line geometry and it's connections.