After shooting many, many rolls of 120 format infrared film I'm convinced that loading a camera in the shade, even in my own shadow, is perfectly ok. The really critical time is in unloading the camera. If the camera doesn't take up the exposed film and backing paper tightly, causing the "soft roll" phenomenon, then the roll is not absolutely light-tight and edge fogging will happen. I have a Seagull 4A103A twin lens reflex camera that does exactly this.