I will end my discussion on the Battle of Dranesville by saying that I think Thomason is wrong in contributing the defeat at Dranesville as a result of carelessness on the part of Stuart. My analysis is that Stuart's error was in placing trust in men who were not worthy of such. As J.B. Jones writes, Stuart was led into a trap. He had no reason to distrust the men who told him about the supply of forage in the small city. He had no reason to believe they would notify the enemy that he was coming. Adding to this scenario was the fact that his pickets, after being attacked by the on-coming Federal force, did not report this fact to Stuart. They failed in their main responsibility.
Now, about the "coincidence" of both Stuart and Federal forces descending on Dranesville on the same day at the same time for the same reason. Well, as NCIS Agent Leroy Jethro Gibbs would say, "there is no such thing as coincidence." It is too much to assume. If Jones is right, and Stuart, in his official report, suggests he was betrayed, then for me this is the more compelling reason than simple carelessness on Stuart's part. Furthermore, McCall writes in his order to Ord that he was in contact with persons unknown who gave him the position and strength of the Confederate pickets. Ord himself writes in his official report that he knew the strength and position of the Confederate pickets. Both Ord and McCall say that they were going to Dranesville for forage.
Underpining this conclusion is Stuart's report, Jones' account, Ord's and McCall's official reports, and the simple fact that I have a hard time believing that both armies headed to Dranesville at the same time to perform the same act. What I believe happened was that Stuart was sent to Dranesville for forage on the word of the men recently released by General Winder. They, in turn, notified McCall that he was coming. The Federals responded and drove in the cavalry pickets, who chose not to notify Stuart of the large Federal force in Dranesville. When Stuart appears to take possession of the roads, he is surprised to find a large Federal force at Dranesville.