What understand from German copyright law at least, it is equally important to actually have damages(at least that is what a FOSS specialized company lawyer explained to me based on some ordinary court cases). That means it might be easier if you have dual licence (and successfully sold it) and can prove that someone did not pay the regular licence fee, so you can be eligible to double the fee. I guess if the money at stake is big enough you find a lawyer. However I guess the case needs to be clear enough because the legal fees will go up as well for failure, I guess.
