So I had a big block of thirty saurus five ranks deep that won a combat vs skaven slaves and clan rats on the flank, and at the end he had four ranks of clan rats and one rank of slaves to my five still, and my opponent said that since he had 5 or more models in the flank I didn't get a rank bonus. I totally get that and still won by a huge margin, but then he said he was steadfast because he had more ranks than me. If I have more ranks but that unit disrupts me, does he get steadfast against me more actual ranks? Sorry it's a lengthy story but it brought up a big debate over what is the right course
Disruption only removes rank bonus, it has no affect on steadfast what-so-ever. BRB Pg 55 (first paragraph on page) "It should be noted that a unit does not lose its steadfast for being disrupted. A flank charge might be able to disrupt a unit, but it can't prevent the warriors in that unit realizing they outnumber the foe."