Nothing will stop them from filing their patent unless you are aware of their filing, and object.
Then, if you were to do something w/ your idea, they may very well sue you, regardless of their patent's invalidity, making the gamble that you'd rather settle than deal with the legal proceedings required to invalidate their patent.
These guys aren't doing it cause they're smart. They're doing it because they think there's easy money to be made, and it's a pain in the ass to defend yourself in court.
This behavor is called patent trolling. I figure any careful reader of Slashdot would recognize this modus operandi, given it's frequency in News for Nerds.
So what can i say?
You must be new here.