Not necessarily. They can have a "we're allowed to sue on your behalf" agreement with the owner. Also, the patent owner could sell it to them for $5K, wait a couple of years, claim that the value has ballooned to $2T, and let them sue.
(Oh, patent owner also owns troll, but you can't know that without spending a few hundred K$)
And if they lose, the patent apparently is worthless, so not much help there.