CMYK vs. RGB Mode: We only accept files in RGB color mode. Has anyone come across?

Question

Adobe Illustrator

There is one overseas factory (large format printing), which writes in the layout requirements: CMYK vs. RGB Mode: We only accept files in RGB color mode. Why is that? To independently then translate into cmyk using some special methods? Or is there something else...

Answer 1

Yes, you thought right. They, in order not to bother you with an envelope in CMYK, will do it themselves. But there is one "but": you cannot see the result of the conversion. Will have to trust them.