Not Deloitte, but used to work for a big company that was as zealous about their logo / stylebook.

I once had the audacity to make a totally internal-only powerpoint where I had a little stick figure guy with the company's logo for a head, just a fun little anthropormophization to make dry material a little more interesting.

One of the marketing execs was in the room. i swear you would have thought I sacrificed a puppy during that meeting, for how outraged and even revolted they were by that.