I know you know more about this stuff than I do, but MSRP is only the suggested retail price? So you say there is a good chance there is a contract between manufactures and retailers as far as the prices get set?
I came across this app just a few minutes ago, heard it's gonna be free tomorrow. I have not used it yet but seems like a really good idea to have. Apple: http://itunes.apple.com/us/app/vehicle-identification-system/id459390791?mt=8 Android: https://market.android.com/details?id=com.apps.Ten8Industries&feature=search_result#?t=W251bGwsMSwyLDEsImNvbS5hcHBzLlRlbjhJbmR1c3RyaWVzIl0.
You also don't bank on one shot stopping a threat. That coupled with adrenaline and the fact that in a critical incident you lose fine motor skills/marksmanship means more rounds fired.
We had a guy who's registration and license was expired for about a week. We reminded him, was very thankful because he forgot all about it and he went on his merry way with no citation. Ran into him the next day, said he got them renewed and thanked us again.
I heard this the other day and forgot until I saw today they were reversing the decision, saves me $2. http://www.reuters.com/article/2011/12/30/us-verizon-fcc-idUSTRE7BT13I20111230
What kind of car were you in? Were you out of place in the neighborhood? How out of date was it? What time of day? Were you cited? Were they searching for a vehicle matching your description? Were they being nice to tell you they were expired? There are usually a lot more circumstances than just "zoomfg expired tags!"