There is a similar kind of thing that goes on in technical sales where I'd blanch I was forced to give the customer either email or IM trails. "They want [...] what???"
"Dear Sir/Madam, your request for a special discount on the software has just been assessed by our pricing and contracts team, and they have responded: you want what [...] discount on this software? Could you please take a long walk off a short pier, and if you get back go [...] yourself and walk off that pier again."
"Okay, I'll let them know we're not going any further than 30%."
There's also the development of an ability to either remain facially unchanged, or smile politely, when some questions or assertions come in.