Reminds me when Paramount started suing Star Trek fans over their fan websites...look where that franchise ended up.
The way an IP specialist put it to me was: if you ever knowingly fail to pursue an infringement claim, you weaken any future IP claims you may pursue.
That is, Paramount couldn't have cared less about the fan websites, but their lawyers were telling them they needed to go after them or they'd weaken their case against true IP thieves.