and the brake pedal in an automatic is the width of both pedals in a manual
Yeah... no.
The clutch would be to the left of both pedals in an automatic. Your foot rests in the empty space left of the brake pedal, usually there's some kind of footrest roughly where the clutch would be. If anything you'd slam on that rest. Lifting your left foot off that rest (where the clutch you intend to slam would be) to hit the center pedal (which is where the brake is in any car) makes zero sense as a potential mixup. Not to mention it would feel extremely unnatural to operate a pedal so far right with your left foot if you tried.
Yeah, no need whatsoever to eat cramped too tightly around a table.