see's the votes against Doflamingo, and the reasons why--triggered
Doflamingo telekinetically controls his threads. They do not go a straight path. When he uses Full Bright, he detaches the threads from his fingers and throws them at an angle to attack his opponent from above. He can literally makes it RAIN Parasito threads, which he does very consistently, as shown in both events he uses it in Dressrosa.
TBH, even if Sans CAN teleport away while caught in Parasito (possible, but I'm not entirely sure he'd be able to use his abilities due to his physical body being drastically weaker than someone like Luffy), Doflamingo still has a wide array of abilities that will assist him should Sans start teleporting all over. Precognition would allow Doffy to react faster to where Sans will appear, allowing him to throw an attack at that location to hit Sans simultaneously. Not to mention that singular threads from Doflamingo are incredibly hard for the eye to see.
Doflamingo's pre-cog and range pretty much give this to him from the start.