Here is another option that might work: It *may* be possible to remove the luggage rack with the seat in place. I haven't tested this, but on my bike, it *looks like* the bolts that secure the rack have captive nuts, in which case you should be able to back them out with a Torx bit without having a wrench on the nut. If that is the case, once you get the rack off, there should be a large opening on each side of the bike, just where the colored bodywork meets the black plastic bodywork. Through that opening, you should then be able to pop the seat loose by pressing the latch backwards.
If this works, it beats the hell out of more violent methods!
EDIT: After a little more probing, I think this is worth a try.
The rack is held on by four large torx bolts that are easily accessible and two smaller ones that are partially covered by the lip of the seat when it's in place. The seat flexes just enough that, if you're careful, it should be possible to get to the smaller bolts and remove them. As the picture shows, with the rack out of the way but the seat still in place, you should have a straight shot at the latch with a long stick.