My company does contract work for a big corporate and in my case they don't generally want access to the code - they'd rather just call me up when there's a pro

My company does contract work for a big corporate and in my case they don't generally want access to the code - they'd rather just call me up when there's a problem as I'm not unreasonable with fees, generally available, and I know my work inside and out. Of course if I'm away and there's an emergency they have everything they need to modify it themselves, including the in-house skills. I wouldn't do anything nefarious like this, but I can relate to the situation of them not wanting/needing day-to-day access to the code.