boiler room

昨日とりあげた場面で探偵のMarloweが刑事に次の台詞を吐きました。
"Aw, keep that crap for the boiler room," I told him.
この "boiler room" が気になりました。何故 "boiler room" なのでしょうか？　調べると "boiler room" には興味深い次の意味の部屋であることが分かりました。
・Oxford English Dictionary: A room used for intensive telephone selling: boiler-room stock salesmen: He is by far the best salesman in his boiler room.
・Word Spy: A room set up as a telemarketing operation, but used to run scams, such as selling fake jewelry or stocks.
"boiler room" の由来がThe Word Detectiveに書かれていましたが、以下はその抜粋です。
As a slang term for such shady enterprises, "boiler room" dates back to the stock swindles of the 1930's, and originally may have referred to the actual basement boiler rooms that are said to have housed banks of early telephone scam artists. The name also might have come from the high pressure atmosphere of such businesses, or from the raucous racket, as loud as a boiler room, of a hundred voices selling schlock.
確かに、おれおれ詐欺を始め、多くの詐欺は電話を使うのが常套手段で、詐欺集団の "boiler room" がＴＶのニュースで映し出されることがありますね。