I love when some people like you focus on one or two links that aren't necessarily valid and only those. While you don't focus on every other link that is legitimate proof. Also, that is such an illogical comparison, all you are doing is attempting to make this suggestion look stupid by creating some imaginary, ridiculous trade. By the way that exclusively wouldn't count as proof if the own of the bud declined it not "especially" because if it was accepted then it is proof, but again that is an illogical comparison. Now I'll criticize in a more polite way. The 1st and 2nd links do not matter, they only had offers of 17 keys they were not sold. Don't include quick sellers they usually take 20-50% off of the actual price. Now, all of your other proofs are good.

Here is some additional proof:

http://www.tf2outpost.com/trade/10135820 Sold for a Black + White Bill's which are 9 keys each 9 + 9 = 18 keys

http://www.tf2outpost.com/trade/10185543 Unsold at current range (19 keys) for 2 weeks

http://www.tf2outpost.com/trade/10651969 Selling for 18 keys w/ strange parts headshot and snipers killed

Sellers on outpost are all either high ballers at 1 bud+ or selling for 17-18

Successful buyers at < 19 keys:

http://www.tf2outpost.com/trade/10443600 Buying for 18 keys and got two in the comments agreeing to 18 keys one with a strange part

http://www.tf2outpost.com/trade/10454447 Added for machina at 16 keys

http://www.tf2outpost.com/trade/10535739 Bought 1 for 16 keys

The evidence is there I say upvote.