So I'm at this critical point in the game, I pull off a spell, he doesn't have dice to dispel (or he did, but failed his roll, I forget which) . . . and just as I'm about to feel triumphant in enacting the effects of the spell — he says with a flip of his hand, "Oh, well. Dispel scroll." And just like that, my game-turning spell goes up in a puff of smoke.
Problem is — there was no way to prove or disprove that he had brought a dispel scroll in his list. Because he didn't have it written up in any way that I could see it.
When I show up at a game, I always have my list printed up — one copy for me, one copy for my opponent. And I create it in Quartermaster, so all of the points are added up, the percentages are right there, and if I spent any of my allotted points on magic items they're right there in black and white for anyone to read.
Frankly, from now on, if someone isn't willing to print up their list ahead of time using either Quartermaster or Army Builder and bring me a copy, I'm not setting up my army at the table.
(I have a similar objection, only scarcely quelled, against battling someone whose army is less than half painted. But that's a gripe for another day.)
What's your position on showing up with a clear army list printed out when you play a game? Do you expect your opponent to show up with a list? And do you exchange lists before the battle, or do you keep them (and your magic items) a secret — yet all the while knowing you're going to have to provide the list at the end of the game, and everything better be on there?
(Side note: Personally, I love having a clear Quartermaster list printed up, just so I have everything I need right in front of me when I'm at the table. I create the list in Quartermaster and then use Adobe Acrobat to type in all of the extra info, like armor saves, ballistic weapon stats, reminders like "+2S ASL" for my characters carrying Great Weapons, etc. It makes the game move so much smoother.)