Here's an example that an LK with 50 dex able to hit a sinx with 300 flee with level 3 MB:
http://calcx.wushuang.ws/pvp.html?cavbLbibCaAbCaYababEdaaaLkababadade5aaaaaaaaakXaaecaaeunyblfgbplHaafFbNfFbNhhhaambkaakfffakaaaahdaaaapaaaaHadaa
It has 100% chance to hit, It's not ignoring flee, it just have a very high HIT rate bonus.
edit: look like the calculator isn't saving the sinx stats, you can edit it yourself