Can a KML Document use a URI as an ID?

Question

Google's KML reference only states that a Document's ID attribute must be unique. Are there any other restrictions on the content used as an ID? Specifically, is there any reason a URI would be an invalid document identifier?

Answer 1

After doing some investigation, Google Earth appears to accept URIs as valid Document IDs. My guess is that it's doing a simple text comparison, since it has no reason to expect that the ID has a special format.