You're correct.

While costs are tracked per token, behind the scenes the longer the response the more it costs to continue generating, so millions of users suddenly thinking they are clever replicating what they read getting it to max output tokens is a substantial increase in underlying costs.

The DeepMind researchers were likely doing that by API call, which they were at least paying for on a per token basis.

And the terms hasn't been updated to prevent it, they've always had this item as prohibited:

Attempt to or assist anyone to reverse engineer, decompile or discover the source code or underlying components of our Services, including our models, algorithms, or systems (except to the extent this restriction is prohibited by applicable law).