I think they need to define sleep opportunity.

If you need to have access to Suitable accommodations or an Rest Facility 10 hours prior to accepting an assignment, then no commuting before a flight.

When jumpseating or riding in the back you don't have;

Rest facility means a bunk or seat accommodation installed in an aircraft that provides a flightcrew member with a sleep opportunity.
or
Suitable accommodation means a temperature-controlled facility with sound mitigation and the ability to control light that provides a flightcrew member with the ability to sleep either in a bed, bunk or in a chair that allows for flat or near flat sleeping position. Suitable accommodation only applies to ground facilities and does not apply to aircraft onboard rest facilities.


I guess boeing is confused too...

"Boeing stated it has concerns about the use of the
phrase “sleep opportunity”
in
the definition. It noted that it considers a “slee
p opportunity” to be a period of time
during which sleep or rest can feasibly occur. Boe
ing suggested that the definition be
revised to read: “Rest facility means a bunk, seat,
room, or other accommodation that
provides a flightcrew member with comfort and quiet
so as to maximize sleep and rest
within a sleep opportunity period."