Stupidity: Why did the bad guys even go for Xander as he was snowboarding down the mountainside? First of all, it was impossible for them to even get to him as the mountainside had several cliffs. Secondly, why did so many go? Wouldn't it be clever to have as few as possible leave in case his snowboarding was simply to draw attention away from an ambush? They knew he was an agent by now and should know he could have gotten reinforcements. Thirdly, they could just have simply waited for him to get to them.
Stupidity: When the policeman comes for the girls, the people run along a straight path, completely straight, without bothering to go over the fence right next to them or run in a different direction.