Ack ack, I think you need to look at the "spirit of the criteria" and less at following it word for word down to a 'T'. The spirit of this criteria/rule/law is that HTC doesn't want any planes in their sky that the oposing side (axis/allied) never actualy engaged in combat with, and there are plenty of examples of aircraft that fit this description and will never be added. However, in the case of the FW187, it was suposedly encountered by the enemy, I think this is one of those situations where it could actualy qualify. Yes, it never was officialy adopted or put to work in the name of the Luftwaffe, but it did encounter allied aircraft over Germany.
There are clear and established guidelines for which planes are added and not added to the game. The FW 187 does not meet any of these guidelines. It never saw any operational service with any Luftwaffe unit. It was never a plane in the Luftwaffe inventory. There is absolutely no evidence or documentation that says the 3 FW 187s that were flown by FW test pilots ever engaged in combat with any Allied plane, let alone shoot one down. There is only anecdotal evidence that says some FW test pilots took off in 3 FW 187s to defend the FW factory from an Allied air attack, that's it, no other evidence. On top of that, only 9 were made. No matter how you try to spin it, the FW 187 does not qualify.
It's so on the border, word for word it shouldn't be allowed by HTC's criteria (I agree it doesn't have to be, it was in the sky but no proof of casualties/damage inflicted/taken, but if there is then that's another thing), but due to actual events that took place during WWII and interpreting that in the spirit of HTC's criteria... well I think unless you are HTC yourself you really don't know and are just slaping down a fellow player's idea while talking out your ass.
It's not "so on the border", it's clearly on the side that disqualifies it to be added to the game. What actual events took place other than it never served in any capacity with the Luftwaffe? If you have any questions what the criteria is for planes to be added to the game, email HTC. I did a few years ago and got a nice reply from HiTech explaining it to me.
ack-ack