Not sure about when most desertions happened but the San Patricios were far enough from home station to cross Mexican lines.
As I mentioned, the Mexicans were soliciting deserters via leaflets. One from Santa Ana, was dated 15 August 1847.
Also, once a unit crosses the line of departure, the plan generally goes out the window. No matter how sharp or well trained, confusion and fatigue rob a unit of its abilities.
We'll never know how many deserters there were in Mexico and 150 years hence, its academic.
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