U.S. courts have very specific rules regarding the admissibility of evidence, generally to make sure that what is offered is a true and fair representation of what it is offered as. Not being able to identify when an image was collected by what sensor and how maintained up through its distribution minimizes the value of google earth imagery in a legal dispute. It's been well established by others that google modifies imagery without documenting those modifications. Wouldn't you want to be able to challenge an image offered in a court case where you had an interest? Any on-the-ball attorney will vigorously question such "evidence."

The USGS recently funded a study to look at the admissibility of imagery as they transitioned from delivering 9x9 inch photographs embossed with a blue ribbon and gold seal. The Department of Justice buys approximately 2,000 USGS aerial photographs per year for civil and criminal cases and they were worried that courts would exclude images that were delivered on CD, DVD or in other digital form. (Full disclosure - I was one of the experts retained to conduct this study.) The results of our investigation are documented in the Journal of Space Law, Volume 33, Number 1, pp 195-219. Email me (mapguyatcrowseydotcom) if you want a PDF copy of this paper.

Adena,

Sure, attorney's face the same budget constraints we face. Occasionally an attorney calls me with a $5,000 fence line dispute and wants me to get satellite imagery and build a demonstrative GIS ... until I gently share that the cost of a Quickbird scene plus my time to assemble a preliminary GIS exceeds the value of the case. In those instances I point them USGS's excellent Earth Explorer and the Ag Gateway for cheap/free imagery.

All the cases I work typically have me secure imagery from the source (USGS, DigitalGlobe, GeoEye, etc.) because we get all the needed metadata with the imagery.

In spite of the issues, I and friends in the legal community who follow this have noticed a handful of cases recently where google earth or similar has been allowed in court. My opinion is that it'll only take one time of getting embarrassed when doing so to put a stop to it, particularly if it's a published case.

The cost of imagery in years past was way out there, but even though high resolution imagery over large areas can get a bit pricey, the cost per unit has gotten very affordable. I'd be surprised if a university level researcher could not secure data only because of cost. With the price of software licenses and hardware to support it, data is a small factor, especially with so many free or nearly free data sources (e.g., NAIP, ASTER, etc.).