JD, Julie here. So Snr Royals can walk right through with their bags. MM is now a Senior Royal so she could potentially be used as a drug mule, carry secret documents, illegal photos or videos, large sums of cash, counterfeit documents, stolen items, without being checked. There in itself is a reason for someone with illegal intentions to back someone to get them into this sort of position. Not saying they did just if there is a crack in any system someone is bound to find and exploit it