The Washington State Patrol went and stepped in it recently, sending out a letter to all licensed gun dealers in Washington, asking them to report the 'names, date of births, addresses, phone numbers, date of transaction and serial number from the purchaser.' for any AR-15's sold since July of 2010.
The whole story is here. Apparently, the State Patrol realized that they were missing an AR-15(remember...law enforcement folks are more responsible than you, and deserve special treatment), and decided that a good way to track it down would be to ask all gun dealers to report every AR sale since their gun went missing.
Engaged heavily in damage control, State Patrol spokesman admits that they should have made it clearer that this was a 'request' and no one is legally obligated to provide any of this data. Almost universally, the gun stores quoted have said no, mostly addressing what a shear pain in the butt it would be, without trying to get in to the politics.
There is some politics involved though...State Representative Matt Shea plans to deliver protest letters signed by 36 state Senators and Representatives to the Governor and head of the State Patrol.
If the State Patrol had provided a serial number for people to keep an eye out for, it would have gone much easier. But, then, they wouldn't have gotten all the juicy data they wanted.
Most alarming to me is that they are asking for records since July...does this mean that this AR could have been missing for almost 9 months before anyone realized it? I guarantee you I KNOW where my AR is.
I almost wish some of the research was done though...I'd be highly curious to see how many EBR's have found loving homes in the last 9 months.