I've been sent a number of CMYK tiff images for some custom processing in Photoshop. These are expensively-shot images (Hasselblad digital body, full studio setup, already processed in Photoshop CC) for expensive glossy magazines. They come from an experienced, professional photography shop. Yet, the tiff files include no color profile, and I've seen the same thing in the past from other sources too.
Hoping for the best, I chose "Do not color manage" in Photoshop and shipped out my modified tiff files without embedded color profiles too.
Is it common for high quality CMYK images to be shipped about without embedded profiles? For RGB images, I'd think that a potentially serious mistake. Is there something about CMYK working practices that makes it acceptable?
Depending on the color workflow (Early Binding, Intermediate Binding, Late Binding) you convert to the right Colorprofile for the output on different stages of Production.
However to work with no colorprofile is never a good idea (as long you want to take control over your colors ^^).