While you might have been able to “gotcha” the court, it would also have been a sure fire way to end up in contempt.
It usually ends up working the other way around. Companies will bend over backwards to assist the government even when the law does not require it or when a warrant would normally be required. When a company is saying otherwise "we will stick it to the man" that is just a show to obtain confidence of customers and prospects. Lavabit [1][2] was a perfect example of what happens when a company tries to fight this paradigm.
[1] - https://en.wikipedia.org/wiki/Lavabit
[2] - https://www.theguardian.com/world/2013/oct/03/lavabit-ladar-...
Canaries also require trust and transparency. Automation is quite common amongst developers. A canary being updated could be automation. Signing can be automated. They might assume that if something is wrong they will be able to stop the automation. This may not be the case. It may be worth noting a judge in the USA can hold someone in contempt for a civil case indefinitely and up to 6 months for a criminal case. That is plenty of time for end-users of a site to be monitored, investigated and prosecuted.
If I were trying to manage such a thing then I would have to create a highly distributed site with signals a government could not easily tamper with and people around the world associated with the non profile could update such as Tor .onion sites, i2p links and the like. This would require friends of the site stay in continuous contact. This could potentially cause more problems for the people not operating from the shadows. The site owner would have to be able to deny any knowledge of the people updating or removing the Tor/I2P links. This also assumes interested parties are even monitoring these links. This would require incredible discipline and opsec, something most people just do not have time for. Yes I am arguing against my own idea.
Continuity, watchdogs, canaries, spook alarms, Deadman PGP switches, even offensive counter-LEO apparatuses.
You can not be compelled to work for free, but you can if you have ever received meaningful compensation.