Here's one such example. A group of journalists in Israel used a web-based machine translation system to translate an invitation from the Dutch Foreign Minister, and the end result very nearly caused a major diplomatic row. Apparently, the system could not differentiate between the Hebrew word for "if" (ha'im) and the Hebrew word for mother (ha'ima). Ouch. Other translation errors included "bandages of the knitted domes" instead of "Dome of the Rock".
The email apparently began "Helloh bud, Enclosed five of the questions in honor of the foreign minister: The mother your visit in Israel is a sleep to the favor or to the bed your mind on the conflict are Israeli Palestinian, and on relational Israel Holland,"
Ho hum. I suspect that causing offence to the Dutch Foreign Minister was NOT the objective the journalists had in mind when they innocently fed their text into the web-based translation tool. I guess the moral is that using one of those web translation tools might be just about OK for getting a general outline of something you can't read, it should never be used to translate important communications that you are going to send to your clients. For that, you need a skilled, qualified, trained, experienced professional translator.
Sure, using a professional translation company costs a little bit of money. But the real cost of this mistake has been that the trip to the Netherlands was cancelled, and the Dutch government is considering filing a formal complaint. Can you afford to risk doing that sort of damage to your relations with your clients? Better by far to incur a small expense and to get it right first time.