The California Rules of Professional Conduct (CRPC) which apply to lawyers in California and by extension their support staff including paralegals provides the following on UPL (Unauthorized Practice of Law):
Rule 1-300 Unauthorized Practice of Law
(A) A member shall not aid any person or entity in the unauthorized practice of law.
(B) A member shall not practice law in a jurisdiction where to do so would be in violation of regulations of the profession in that jurisdiction
This, of course, is to be read in concert with the prohibition in Business and Professions code 6450. The bottom line for the paralegal is that not only can he or she not engage in UPL, but also they cannot aid or assist anyone in UPL. This is an area in which paralegals need to be vigilant to avoid trouble and potential liability.