A 1.1 kg lens is not a problem for the camera mount under normal usage.
The Pentax lens mount is pretty solidly build , so is the stainless steel internal chasis, even for the K100D. But if you feel more comfortable and in control by holding the lens, why not ?
If either lens or camera hits the concrete floor , that's a problem.
Your friend may have had Entry-level Canons in mind....different subject...
I use the presence of a collar mount on the lens as a rough guide. A lens with a tripod collar mount is meant to be supported by holding the lens body, and that's what I do. I'm usually more worried about the lens side of the mount - it sometimes looks flimsy.