Door to door utility canvassers are subject to the travelling salesman exception to the statute, since although the utility has the final power to ratify the sale or not , gaining the consent of the customer is the work of the salesman.
Although the portal-to-portal act puts some security screening time outside the Labor act's compensation mechanism, state law might cover the claim, since state law does not mimic the exception, and work need not involve exertion.
http://www.opn.ca6.uscourts.gov/opinions.pdf/18a0207p-06.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.