Someone offering up a flight to grab is not "open" or open time. The person offers it up and it's their's until someone can grab it. If it doesn't get grabbed the owner of the trip or segment is still on the hook for it.
(I know you know this, but some people may not).

The definition does not say anything specific about "Trips that are offered up as a grab" or any language like that. Looking further in the the Contract...the Scheduling Stand notes say specifically that pilot to pilot pick ups for Reserves flying on days off is not allowed. It doesn't however say why it's not allowed. Something Something....they don't trust us to not screw up our availability...or us it as a tool to get out of Reserve by maxing out block maybe? Still doesn't make that much sense. So, yeah, I guess I would like to know why specifically