There's basically 0 chance this would be legal if you're a private company.
In the USA it would absolutely be legal and you would be bound by a binding arbitration clause and a non-disclosure + non-disparagement clause.
You might even be bound by a license / ToS which prevents you from comparing the capabilities of that system against a better system[1].
[1] https://www.brentozar.com/archive/2018/05/the-dewitt-clause-...
Reminds me of the pre-internet days, when online access was charged by the minute. You'd better be damned sure you knew exactly what you were looking for before you connected to CompuServe, The Source, Delphi, or whatever.
I think today, people don't grok what a miracle it is that in many circumstances they can just aimlessly "surf" the internet and not get any incremental charges.
Most providers bury this cost in their revenue model and hide it from users. While PACER is probably charging more than is necessary, they’re definitely not burying it, and I’m honestly quite happy to see that.
There is an interesting parallel in that common and widespread reaction that match issues we’ve seen with essential workers during the pandemic, where for example a customer will say “Why should I wear a mask? There’s no one in here!”, somehow failing to recognize the worker as a human being in the process.
So, to translate the PACER pricing objection into the human equivalent, I present a question:
Do human librarians deserve to be paid a wage for performing a search that finds no results, or should their wages be docked if they can’t find anything?
The entire economic system of the Internet is built on the fact that the marginal cost of every action is essentially $0. It's certainly no where remotely close to 10 cents. More like 10 millionths of a cent.
Or think of it this way... how often would you go to a library or bookstore that charged you simply for looking around (additional charges apply for each aisle you walk down)?