Sacrosanct
Legend
So the dragon got to be hundreds (thousands?) of years old by being dumb in a fight? Sorry, my v-tude hurts. And if there werent any casters present, why wouldnt the dragon just attack the halfling? I've seen you trot out this example like at least 10 times. "One time my DM played a dragon real stupid and I cheesed the fight and you can too!" Things that force saves arent great in many games for blowing LR's. It depends on the DM.
If you've seen me trot out that example 10 times, then why do you keep ignoring everything behind it and I have to keep explaining it? An adult white dragon has an INT of 8. Maybe, just maybe, it got to be that old because it's a freaking dragon that eats anything that gets in its way. There are a lot of reasons why a creature can get as big or live as long as it does without having to be super smart, especially if it has many other attributes that put it in a high position on the food chain (like brute strength, breath weapons, etc).
Also, if you did see me trot this out 10 times (I think I've only mentioned it three times, but whatever), they why don't you remember that I wasn't the only one there. Just because I said the dragon didn't know there were wizards, doesn't mean everyone else in the party was hidden. For one, last time I checked, dragons (especially INT 8 ones) didn't have some divining power that allowed them to know the exact classes of every creature they could see. How was it supposed to know that PC 4 over there was an Eldritch knight? As far as it knew, it was just a human in armor with a sword. Secondly, the other PCs who weren't casters were positioned fairly far away and they were the ones to lure him out while I was alongside the cavern wall waiting to ambush it. And thirdly, when planning combat, there are a lot more non-mechanical factors regarding strengths and weaknesses. Knowing that a monster is prideful and brutish and using that weakness against it isn't "cheesing the fight" any more than using fire against a troll is. Maybe you like to metagame and view creatures only through stats written in a stat block. But many of us do not. That attitude reeks of one-true-wayism to insult another play experience because they didn't metagame like you.