Originally Posted by
Grog
I say this as someone who sides with you 100% on the issue itself. People should generally be willing to allow movement unless there's an underlying fragility/placement issue with the contents--and sometimes there is.
If the contents of the bag are truly fragile, then it should be under the seat in front of the passenger where it can be watched. After all, contents in the overhead can shift during flight.
Of course, I get your point about the jacket (and especially if the bag is already efficiently using the space, i.e., at the edge of the bin), but I can't think of ANY reasonable reason someone should decline to move OR allow their bag to be moved slightly.