Update:
So, I took the NEW 2018 MBP into a certified support center. They cleaned the KB, took the key apart, etc. It still sticks. They tried to order a new KB (because you can't just replace a single key on these machines), Apple said it will take 1 month to get the parts. The support center tried to send it to Apple to have them fix it (which would be 5-7 days)... now here's where it gets crazy...
The process for sending the unit back requires the use of an online ticket system. When the support center fills out the form, it sends back an error saying that my BRAND NEW MBP cannot be accepted by Apple for repair as of now. In order to get a full replacement Apple needs to go through their process to try and fix it first... but I can't send it back to Apple as their process is broken (going on 2 weeks now). So, I can't return it and it will take a month to get the parts.
I called Apple support and it got escalated and the guy I talked to said Apple would never replace it and I'd probably have to pay to get it fixed (even though I did nothing wrong and went through the appropriate channels to get it fixed). He also said that the support center I'm using is crazy and they can certainly send it back to Apple to get fixed. I watch the guy at the support center go through the process 2 times in front of me and I saw the error... it flat out says Apple will not accept the new MBP with touchbars back for repair as of now. He tried calling Apple too, same response. The customer facing side of Apple support WILL NOT talk to the stores or certified support centers - so I can't get them both on the phone to see they are contradicting themselves.
I am sooooooooo fricken disappointed. I've been an Apple user for 15 years and I've never had any problems. Now the one time I have a problem no one can help. I'm now computer-less (which means I can't work) for 1.5 months unless I want to use a portable machine in clamshell mode tethered to a usb-c hub. It's not the end of the world or anything, but Apple has lost a ton of respect from me now.
