When you sit in bulkhead seats, you cannot have any luggage at your feet, for both take-off and landing, but once airborne you are (supposed) to be able to retrieve your luggage (which might have a laptop) for use during the flight--if bulkhead pax can retrieve items from the overhead compartments, why shouldn't other pax be allowed do it too?
[From a comment in one of the "news" feeds, you are supposed to ask "permission" from a FA when retrieving items from the overhead bin.]

Quoted from abcnews: "If there is something you need then by all means you have to talk to the flight attendant, don't touch them," said Schiavo.