Not really new, but certainly worrying. I have been reading negative reviews of postal services where the reviewer claimed what you said for quite a while (now and then, and for all couriers)...

Personally, I am always worried near Christmas because AusPost for example has casuals who don't really care, so they can very well do that and then claim it must have been a neighbour.

I remember that I often stated that the courier could take a photo and run away when they first introduced photos as proof. Photos are only valid with honest couriers, so if you cannot find your item you have an idea, but not with thieves of course.

Once something strange happened to me, although it was more incompetence than theft I think.

I was waiting for a parcel from Germany with signature on delivery and the newbie thought it meant his signature (not mine) and on top of that left the parcel in front of my door (not even behind the screen door) in an apartment building, and of course the parcel disappeared. I was fully compensated, but the item was a bargain, and I was only compensated for what I had paid of course, not for its average price, so it was very annoying. At that time there were people in the building who had done weird things to others and were then kicked out. I think they stole it, but I didn't tell them because when other neighbours complained about something they were quite aggressive, so I thought I would just forget about it, as I had been compensated anyway.