I've done four flights this year on United with the EVOC bag, and haven't paid anything.

Every time I fly I check in through the United app, and then note that I will be checking in one "normal" bag (I carry on my suitcase).

When I arrive at the airport I check in with the Premier desk, and hand over the bike bag. Some have asked if it was a bike, some haven't, but I've never been charged for it.

I'm not sure if they are being nice and igorning the fee due to status, or they don't feel like changing the one checked bag I have already confirmed to actually list an oversize bag, but this method hasn't failed me yet.

Also, I'm a silver on United, it's not like I'm getting the super-preferential treatment of a 1k or GS.