Sequestrium 

Specifically, a tent area inside of the main playing area at the 2007 World Series of Poker. The "tent" was used to hold final tables which were being simulcast on the internet and therefore had to be held in secret to prevent player collusion.
Sequestrium was originally thought to be a portmanteau of atrium and sequester but after outrage at the entire idea of preventing family, friends and fans from viewing final table action, many felt the entire idea was insane, so the combination of sequester and sanitarium was suggested.

Generally, any hiding or sequestering of events that should or could be open to the public.

The Pentagon is the largest sequestrium in the world.

The sequestrium at the 2007 World Series of Poker was a public relations nightmare.

Sequestrium by Poker Shrink July 9, 2009

sequestrian 

a government worker who takes up horseback riding during a mandatory unpaid furlough

Its great to see Bob become quite the sequestrian during his unpaid time off.

sequestrian by monkeyman1968 March 4, 2013

sequestrian 

Like an equestrian, a person who rides alone on the occasional time they are out of their house due to the 10 ft rule during the Covid-19 days. Only difference to an equestrian is a sequestrian doesn't need a horse.

Finally escaping the confines of my house, I went to the park for some fresh air with fellow sequestrians, all of us keeping our unspoken 10 ft lanes.

sequestrian by BratUs March 23, 2020

Sequestrian 

1. Any person who has been sequestered, isolated, or quarantined for any reason.

2. An ascetic who voluntarily removes themselves from society solely for the purpose of improvising their horsemanship.

During the COVID-19 pandemic all of us were sequestrians, but only some of us learned more about horses during social distancing.

Sequestrian by Spencer Michaels April 22, 2020