When a workplace gets "upgraded" to open plan, if two or more workers refuse to come in out of protest, they cannot be fired. Sounds like a great way to work from home for as long as open plan lasts. (IANAL)
The law we enforce gives employees the right to act together to try to improve their pay and working conditions, with or without a union.
Is the activity concerted?
Generally, this requires two or more employees acting together to improve wages or working conditions, but the action of a single employee may be considered concerted if he or she involves co-workers before acting, or acts on behalf of others.
Does it seek to benefit other employees?
Will the improvements sought – whether in pay, hours, safety, workload, or other terms of employment – benefit more than just the employee taking action? Or is the action more along the lines of a personal gripe, which is not protected?
See my relevent comment yesterday: https://news.ycombinator.com/item?id=15253333
(But do talk to an attorney before taking internet advice.)