Unsold at 2 or higher:

http://www.tf2outpost.com/trade/10544931 - 2 keys 1 ref

http://puu.sh/2OyCH/6b444b962b.jpg - 2 keys

http://www.tf2outpost.com/trade/10548626 - 2 keys

http://www.tf2outpost.com/trade/10624667 - 2 keys

http://www.tf2outpost.com/trade/10541791 - two unsold at 2 keys

http://www.tf2outpost.com/trade/10612503 - unsold at 2 keys

http://www.tf2outpost.com/trade/10468819 - unsold at 2 keys

http://www.tf2outpost.com/trade/10023053 - unsold at 2 keys

Unsold above 1.5 (and below 2):

http://www.tf2outpost.com/trade/10443099 - 1 key 4 ref

http://bazaar.tf/trade/203665 - 1 key 4 ref

http://www.tf2outpost.com/trade/10613509 - 1 key 3 ref

Buying/bought/Selling for 1.5 or lower:

http://puu.sh/2OyB2/28d5ffd6c0.jpg - selling for 1.5

http://www.tf2outpost.com/trade/10613178 - selling for 1.5

http://www.tf2outpost.com/trade/10418180 - sold for 7 ref

http://bazaar.tf/trade/107948 - potentially bought some for 6 ref? He has a lot in his bp but barely any views on his trade

The case of Goo Glue.

http://tf2tp.com/trade.php?trade=9398585 - unsold at 2 keys

http://tf2tp.com/trade.php?trade=9401357 - unsold at 2 keys

http://tf2tp.com/trade.php?trade=9401492 - unsold at 2 keys

http://tf2tp.com/trade.php?trade=9403843 - unsold at 1.5 keys

http://tf2tp.com/trade.php?trade=9404151 - unsold at 1.5 keys

http://i.imgur.com/fFt8K5g.png - our brave warrior sells it for 1 key

Offers:

http://www.tf2outpost.com/trade/10038550 - highest / only offer after 1 week, 1 key 1 ref

http://www.tf2outpost.com/trade/10526259 - no offers

http://www.tf2outpost.com/trade/10546811 - no offers (wants bp.tf prices)

http://www.tf2outpost.com/trade/10517676 - no offers

http://www.tf2outpost.com/trade/10576666 - no offers

http://www.tf2outpost.com/trade/10020598 - no offers

http://bazaar.tf/trade/183930 - no offer after 3 weeks!

http://tf2tp.com/searchMongo72.php - nobody is even buying them on this website

Counter proof:

http://www.tf2outpost.com/trade/9832490 - probably sold one for 2 keys (genuine collector I think)

http://www.tf2outpost.com/trade/10612728 - sold for two keys?

http://backpack.tf/vote/id/5188b9854bd7b8806f00000a - I am aware this exists, I think my proof is slightly better (includes a good 95% of every trade I could find anywhere) and I think he is playing it far too safe to ensure his price change passes. Two people able to sell for two keys does not mean the max end should be two keys.. If say 5, or 10 etc could sell successfully then by all means his suggestion is more accurate :)

To sum up:

Nobody is buying them unless it is a quickseller (have little / no success buying under 1 key).

Nobody is buying them at the current price = no demand = price drops

Multiple trades with no offers = no demand = price drops

Multiple trades / sales at 1.5 keys and potentially less

The case of Goo' Glue highlights everything.

I was tempted to put the price range at 1-1.5 keys but I figured thats too big a drop for most people to deal with and I only have one piece of proof that 1 key is possible because no-one is buying them...