It is generally known that in the case of multiple node or communication failures atomic commit protocols cannot avoid blocking. While in wired networks such situations are rare because of low failure probabilities, mobile ad-hoch networks (MANETs) are considered to be a more challenging. In this technical report I present a probabilistic model to predict the abort and blocking risks of distrubted atomic transactions for arbitrary MANET scenarios. The model presented is applied to a standard MANET scenario to demonstrate the blocking risks to be expected.