I'm a nice guy asshole. In short I enjoy friendly, non overly competitive games. But also like rules to be followed and if my opponent gets over competitive (to the point of rules bending or cheating) I call it as I see it.
That whole roll to start? I'd have said "Their is only one roll to start the game, deployment and starting are the same, you can look this up in the rules book if you want, no need for a reroll. We both legitly rolled for the only thing to roll on." If they really want to go first I might let them as a friendly game, but if they are just so competitive that they insist on rerolling screw'em.
Picking up the dice and changing it. "When I ask to see what you rolled that means dont touch the dice, I want to see what you rolled not have you manhandle it, you changed the numbers and thats cheating." I will say that and loudly if I must.
Rolling when your not looking "I wasnt looking none of that counts please roll again."
I do have a habit of asking to check rules on a book. If I trust the person I'm happy to do it after the game, if I dont I want to see them now. This is because I find many of my friends unintentionally get rules wrong. If someone flat out says "No you cant look to confirm my claim" well thats fine, we'll have to ignore that rule or you could go. "No no chaos launcher is Heavy 1 Str 3 AP 6" when he squeels thats wrong... well he'll just have to prove it wont he.
As I say in frinedly games I dont much care, if we screw the rules up because... their is a lot of rules, that happens. But against cheating us asshats... they bring out the best in me.