Answering my own question: I used a template to shut it off for everyone. 
They can opt-in, rather than me needing to deal with a bunch of service tickets asking to shut it off. 

It did not work for me. I turned off in the templates the AI options but it is still showing on settings menu when the users login to ring central app.  Did you created a new template for this purpose?  

Is it possible to remove or disable it?  

I doubt we can remove it, it’s one of those features everyone brags about having in their systems these days and RC is no different.  

If users turn it on, they’re on their own. 

I created a new template to turn it off for existing users. When I create new users I have to shut it off manually. 

It’s possible to be removed. You just need to contact RC about removing AI assistant for your account. 

Despite the support article stating that “admins can turn the AI assistant on or off for their organization through the RingCentral Admin Portal”, I was informed by RC Support that it could only be done by level 3 RC Support.

Thanks for bringing this to my attention, Tim! I’m reaching out to the team to understand the KB and if we can make some updates.

AI Assistant feature can be toggled on or off by admins per user directly through the RingCentral Admin Portal. However, if the request is to permanently remove or disable the feature entirely at the account level, that does require assistance from Tier 3 (T3) Support.

Hope this clears it up!

It does not clear it up. 

The steps in the support article I mention above do not in fact disable the AI assistant.  So I would dispute the claim that AI Assistant feature can be toggled on or off by admins per user directly through the RingCentral Admin Portal.  This does not work, which is what others are reporting in the thread.

I do not want to permanently disable or remove it.  I want to be able to toggle it off temporarily.  This seems to be the functionality RC means to offer, it just doesn’t work properly.