Let me walk you through your own example....
I'm a terrorist. I register my drone as John Smith. I put in some address and a phone number to a pre-paid cell phone that I bought for $20. This took me all of 45 minutes (ok, an hour if the cell store is far away). I then create a drone to deliver a bomb. Now, I'll just ignore the obvious situation... I create a bomb that is delivered by the drone. What I do is spend a lot of time, not creating a bomb that I can blow up upon delivery (because that would be _way_ to easy and I'm a much more James Bond villain type of terrorist)... I take the time to create a bomb that only blows up with the battery is removed. Now, I fly that drone to some busy spot and land it. A first responder then gets the drone and calls me (remember, I'm a sophisticated terrorist so I put the registration on the drone (because that is the only situation where your scenario works.... I'm a law "abiding person" who put their registration on the drone). The first responder then calls me and as a "law abiding person" I tell them, yeah... my bad, I accidentally flew that drone and landed it next to the White House. So now what? They are safe to open the drone? Oh? They don't remove the battery? Well, without the registration they don't open the battery either. However, under my frame of mind, they treat the drone as it could explode. Who's going to keep that first responder alive in this situation... you line of thinking or mine?
So I've just shot your situation full of problems. Truth is, you could come keep coming up with more and they will be just as flawed as this one.
But wait... you did....
Well, I already showed that this is _easily_ not the case.... but seriously, we are talking about drone and you are now talking about luggage and vehicles? I'm going to guess you mean a drone inside if luggage or a vehicle? What the #$%$%? That would just put the bomb inside.... the VEHICLE OR LUGGAGE! They don't need a drone for that! I guess you are going to have first responders open up the luggage, find the drone and then not want to open the drone? Seriously?
YES!!!!!!! If this is an _actual_ problem... people rigging the drone to explode if the battery is removed THEY SHOULD ALWAYS TREAT IS AS SUCH.... external registration or not! The problem goes back to the stupid registration itself.
No... no it does not. I just gave you something I came up with over the span of 10 minutes and 1 hour's worth of execution that proves this wrong. The new rule.... could get people killed.