The drills have changed over the decades and depending on the line. In the old days we had to go to our cabins, put on our vest and line up at the life boat for instructions and roll call (That was RCCL). It was hot and uncomfortable if you were on the sunny side of the ship but you knew how to put on the vest and where to go. The line also knew you were in the popper place. We were all pushed and packed into formation for the drill.
On Celebrity in Europe we did the drill at assigned meeting places, roll call done but did not walk out to the life boats or put vest on (that drill took a long time because of the different languages they did it in)
On Carnival they take a head count but no roll call, no putting vest on. If you meet in a lounge they do walk you up to and line you up by your life boat or raft (on the glory I was assigned to a raft....... guess that's what you get when you book the cheap cabin). On another Carnival Cruise we had a passenger pass out from the heat during the drill.
In Alaska on Princess we got to the ship late at night and missed the drill, we were told to do the make up drill the next day, we forgot and the line never said anything to us about missing it. I did find out on my own where my lifeboat was.
The drills are not fun and can be uncomfortable if it is hot or too cold out, but look what happens when the drills are not done like on the Costa Concordia. I am happy to put up with the 1/2 hour of not fun at the beginning of my cruise to feel relaxed for the rest of my trip.