That's right but the problem can be that if parked on a steep hill, the pin can shear off so the car runs off on it's own. That's why you should never put it into P while still moving and always use the handbrake as well.
Shear off or be very hard to move the shift lever out of Park. Roughly a month ago there was a guy on DiscoWeb troubleshooting a stuck in Park problem for several days. It ended up being exactly that he was parked on a steep hill without the Park Brake engaged, not the electrical issues he was expecting.
I always find myself pulling on the handbrake before putting it into park for that reason..
All autos are like that. It is only a problem if you do it the wrong way round.
If you park on a hill, hold on footbrake, leave in D, put handbrake on as stated, then put into park and finally ignition off.
Wrong way is hold on footbrake, put into park, turn off ignition and take foot off footbrake. This way the transmission rolls back and takes the backlash out of the gears. That is why it is difficult to get it out of gear. The cogs are holding the weight of the car.
I always take it out of Drive at lights (I had to think carefully about that, because it's sub-conscious now). Maybe it just reminds me of a manual, being able to move the stick. When I started driving the Defender auto 15 yrs ago it was way back before I understood the anatomy of the gearbox though I'm not saying i understand it much better now :o) ] and I didn't want to create any unnecessary stresses on a car I will take to the grave, and now it's just become the way I drive.
The parking pawl on some (other make) autos allows a lot of wheel movement, could push the car forward/backward a foot. Volvos?
Guys, if you really want to know about auto transmissions and the damage you can do to them, have a look at this resource. It is the best I have ever seen on auto transmissions and there are hours of watching. It is Richard's disassembly videos you need to look at.