How the US ensured that its weapons and equipment don't fall into Al-Qa`idah hands

"American and other Western intelligence officials have expressed concern that some of the more than 100 rebel formations fighting inside Syria may have ties to Al Qaeda that they could exploit as security worsens in the country or after the collapse of the government...A small number of C.I.A. officers have been operating secretly in southern Turkey for several weeks, helping allies decide which Syrian opposition fighters across the border will receive weapons to fight the government."  I am assured that the US has a full-proof system at hand.  The CIA operatives ask the person in question: are you with Al-Qa`idah? If the person says no, he is told: take the weapons AND money and run.  If he says yes, he is told: not good. Take the money and weapons and run but don't use against us one day, ok?