I guess it is risky. Many people see finding next job before leaving previous one as the responsible thing to do. Especially if you live in an expensive location or have family or other financial obligations that simply needs to be paid.
Technically, you can find "temporary" job in smaller company and then move to the company you "really" want to work in. It just seem to me somewhat jerk move toward that smaller company.
Back in AT&T around 2005-2006 a "change of guard" occurred and a very technical team supporting SAP systems lost about half their staff to HP within 3 months. Rumor has it that at&t upper-management had a conversation with HP and a few other people who wanted to go had the door shut in their face.
I know of at least one person who had to quit her job... wait 2 weeks... then HP picked her up. Risky indeed if HP couldn't make good on their promise, but it worked that time.
A strike involves work stoppage, it's a very different tactic than mass resignation.
In 1999, Major League Umpires Association (MLUA) were not able to legally go strike so they opted to use mass resignation as their negotiation strategy. It backfired, cost 22 umpires their careers and led to decertification of the union.
Sickouts are commonly illegal. Though it is usually impossible to punish the individuals for calling in sick, an organization that promotes it - such as union - may suffer consequences, and organizing such thing may be a firing offense.
