I think all our shipping has a tracking number with Royal Mail - no extra charge.

We also don't make you buy a T-shirt or Coffee Mug for stealth shipping - they throw in some other free stuff at no additional charge to disguise the contents.
And, so far, we don't charge extra for a guaranteed delivery. The official policy is a little fuzzy on this, but I've never known them to not replace a shipment if the customer reported it as missing or seized.
I think they like treating it on a case by case basis until it happens so much it requires an extra charge - that way, management can pass it off as a value-added service rather than "now we're charging you for something that used to be free"