Project Fi will take your Google Voice number

You never cancel a phone line with a number you wish to keep. When you port the number away, the losing carrier will cancel the line of service since the number is gone from their network. You can’t port a number after you’ve canceled the line of service.

That's just the way phone companies work. If I go to AT&T this morning and cancel my account, that number is gone. I get that Google owning two things that look like phone companies could confuse people, but under no circumstances would I ever cancel the service on a number I still needed. And like OP said, I know from my experience that Google almost crossed over into belligerence in trying to tell me the implications of porting my voice number. Even if I didn't understand the technical terms, the sheer urgency of the messaging should give you pause about taking any action lightly.

Yeah, the post is a bit ambiguous but seems like you may be right. If OP had GV, then ported to Fi, and then cancelled Fi service without porting his number that would fit with the complaint in the post.

I'm actually somewhat less sympathetic in that case. When you cancel phone service without porting, you lose your number. That's how the phone system has operated for decades.

Why someone would assume that cancelling phone service would somehow automatically sign you up for a different service is beyond me.

But I suppose the confusion is related to people thinking GV and Fi are "the same" or "built on each other" (e.g. see comment from a Googler elsewhere in this thread) since both services give you a phone number and both services are run by Google.

In fact they are essentially entirely separate services from the perspective of the phone network. GV is based on Bandwidth.com's landline VoIP numbers, while Fi numbers are actually registered by T-Mobile.

Not if you like a smidgen of privacy.

Regardless of what that page says, it's been common knowledge that people have lost their number when trying to port it out of Google Voice. It's interesting to see it's still an issue and applies to Project Fi as well.

My Google Voice account is older than 7 years. I specifically remember choosing to get a new number instead of porting my number to Google Voice because of the stories about people unable to port it out.

I haven't heard of any court action, but if your number is already reassigned to someone what's your recourse?