"Voyage cancellation insurance" was an odd concept for Maltz. But he said that leng chach mab ("voyage emergency contract") might cover it. leng chach mab is not a term or phrase he had heard before, but he said Klingons would understand it meant an agreement about who's responsible for what if something goes wrong during a journey.

In the Netflix subtitles, a Netflix account is referred to as a mab. Okrand agreed and added that:

It follows that "register for" or "sign up for" (an account) would be qI' "sign [a treaty]."  So "register for an account" is mab qI'.

Maltz says "sign/log in" is ngaQHa'moH (and "sign out" is ngaQmoH). People say mab ngaQmoH and so on, but this is a special formation, special argot, frozen form.  Maltz said he thinks this may have been shortened from an earlier way to say it, something like mab Hung lojmIt ngaQmoH.

To "sign up" for an event is something else. That would be jeS 'e' Sap "volunteer to participate" (even if the signing up isn't all that voluntary).  You'd say the same thing for signing up for something in advance and for deciding on the spot to participate in an event that's ongoing or about to start.