Fired up my RC2 today and see a popup message:
Login session expiring
Your login will expire in 28 days. Login again required after expiration. Flight attitude and distance limits may apply if not logged in. Connect and update account info in time to keep using app.

I've never seen this before. I've finally got the RC2 and Mini 4 working properly, last thing I want to do is connect the RC2 to the internet and update the app, lol.

Anyone know if I log out of y DJI account, and back in on my laptop, if this will be sufficient, or do I have to do it on the RC2?

You say " connect and update .........." , is it obligatory to update the controller/App etc. each time it is connected to the internet ?
I would hope not.
With one exception it certainly is not when using a phone.
The exception being with an FPV, when I connected the phone to the goggles to get the flightlogs and the  phone had wifi switched on.I won't make that mistake again.

The login will almost certainly have to be performed on the RC.

You have to do the logout and login on the RC2.  If a firmware update prompt occurs just disregard it if you desire not to update.  

Hi, Manitobahunter. Thank you for reaching out. You'll need to log out/login directly from the DJI Fly app on your RC2. In DJI Fly 1.12.4 and later versions, an account remains in the login state for 90 days after the login even if the app is disconnected from the network, and a reminder will be pushed before the login expires.

Thanks DJI Gamora, and everyone else for your replies. The RC2 had indeed logged out of my account. Kind of unusual but I just had to connect it to wifi and it logged me in without me doing anything, and then I quickly disconnected from wifi before it got any other ideas