Sorry mate I've said it before and I'll say it again, people need to stop underestimating the severity of importing illegal substances. It's NOT the same as getting weed through the post UK to UK. Different Police forces will take it with different levels of severity, but the crime is not *possession/possession with intent to supply* it's *importation to avoid prohibition* which is far more serious and as a minimum you'll get a drugs rehab course and a caution, (which your employer will be made aware of meaning if you work in NHS or Civil Service or any job that requires CRB checks you're now unemployed).
You are absolutely right that denial is the best course of action, but all Police aren't that stupid. Accept the package, open her up and 10 minutes later "knock knock" you've got the old bill at your door.
This sort of thing is so easy for various Police forces to do (low hanging fruit) and is classed as a serious crime for their numbers, so yeah, they will do you if they can. People like TGD are professionals, they calculate the risks, people ordering illegal items like cannabis from places like Thailand (to their own homes) and thinking its "no big deal" are very, very much mistaken.
Have a look at Reddit. Plenty of threads of people now having to do weekly piss tests on some shitty rehab course because they imported weed and got caught.