Partizans

[Green]

Jonny, as far as I am aware, there is no Morale check, so the Morale rating is not relevant. The User Manual says that;

"Enemy units moving in Travel Mode are subject to possible Disruption and loss of remaining Movement Points. The probability of this happening is determined on a hex-by-hex basis using the Deception Effect probability."

The deception range and the effect percentage are given in the parameter data. Whether or not you have been unlucky in this particular instance would depend on these values, the total number of units involved and the numbers of hexes each unit entered within the range.

Generally the parameter values are not large so you would not expect mass disruptions. The only exception I can think of is in El Alamein '42 but these values are used by Deception units (LRDG units) not Partisans. 

John