Prove you are a client of another broker that's having big problems now and we'll give you a welcome bonus - definitely vultures.
I've seen broker wars before, but this is something of a new low.
Nevertheless, I'm inclined to consider this phrase as exaggeration during forum debates, since there is not such an official information on the company's web-page. I don't have your experience in "broker wars", but in my opinion such a measure in the scales of many brokerage companies could significantly reduce number of scam-companies.