When the Golden Gate Bridge was being built, the ferry companies (who would be put out of business by the bridge) tried to sue the bridge to death with something like 2000 trivial lawsuits. While each of these was easily defeated, the only thing that stopped the ferry companies was that the local populace boycotted the ferries until they stopped the lawsuits.
So yes, it's been done before, is probably being done now, and will happen again. You can counter-sue trivial lawsuits to make the plaintiff go away (and stop filing suits against you), but it takes some work and laying out some money to lawyers.
Thanks for the background. This whole thing strikes me as a horrible loophole in the legal system. I'd imagine the same is true in most western countries.
Sadly it is the same in most western countries, however if you sue me because I wore a pink hat (frivolous lawsuit) I have the right to counter-sue you (which would be a non-frivolous lawsuit). Yours would be thrown-out and cost you money and probably a lot to get a lawyer to take it on, mine however would likely be taken on on a no-win-no-fee basis by basically any lawyer because it would be so easy to win. So your suit would cost you money, and mine would likely cost me nothing or make me money.
So yes the loophole is there, but the loophole itself is kind of self destructive for anyone dumb enough to try it.
So yes, it's been done before, is probably being done now, and will happen again. You can counter-sue trivial lawsuits to make the plaintiff go away (and stop filing suits against you), but it takes some work and laying out some money to lawyers.