YES!!! I can confirm this 100%......as a US citizen on the Canada /US border I am very aware that the US cannot turn you away HOWEVER the ferry in RT will not let you on with a red or orange QR code, no ifs and or buts.

I almost found this out the very hard way as my portal application gave me the orange because of a last minute glitch where my test didn't upload properly, I then uploaded it 2 more times and it finally went through and I was approved but there was no way they were letting me on that ferry without a green QR code. Now I don't know about water taxi, they may have the same rules as the ferry companies.