Back in the day when I was working with a general contractor one thing the boss drummed into our heads was that it was hands off anything in the house - you do not even get a drink of water without permission. You’re not family, you’re not friends, you’re there to do a job. (Of course, if the home owner offers you may accept, but never ever assume)
The nuts are their for the Queen and, presumably, her family and anyone she invites to indulge. Seriously, people, exercise some restraint. You’re there as security, not a guest. Swiping nuts or candy strikes me as unprofessional.