For me personally, the low open is not an issue. The way I think of it is that so long as the market opens below resistance it has to "prove" itself by trading through resistance before filling the order. Opening too high is much of a concern for me as it can screw up the trade parameters, and more importantly, can preclude a fading market. A fading market is a surefire way to get whipsawed which is why I try to set opening parameters for my trade.
I know that some traders would void the trade since the low open breached support. When you have the market show support, and then break it, to them that shows a lack of strength in the support and a reason to pull the order. But since we were only looking to buy I'm still okay with it.
Erich