Association does not imply causality. It is measure of co-occurrence, not cause and effect.
Though the computation of associated rule can be automated, the analyst should be warned that such association may produce unreasonable rule such as beer -> diaper. Unless the sales will really increase by putting the associated product together, we shall not take the hypothesis that produced by market Basket Analysis as the truth from data. Testing such hypothesis with real sales data would be necessary.
Computation of Market Basket Analysis grow exponentially with the number of items