Leeway Mechanic

Hello Everyone,
As almost everyone noticed leeway mechanic has been introduced on Warmane since some time.
Documenting a bit about Leeway mechanic that has been implemented on wotlk servers I found out how it seems it should work, please correct me if I am wrong:

"If you and your target are running, the game client will give you a +2.5 yard leeway range (someone says +2.66), same goes for your target, basically the range indicator for your melee abilities will be white when you're within 7.5 (7.66) yards of the target(point to point). The server should allow you to cast your melee abilties as well as auto-attack during this mechanic.

There are some conditions to the mechanic though:
*Both you and the target has to be running/moving

*Leeway mechanic will immediately stop if you or your target becomes slowed to more than -29% of normal run speed(-30% is when your character will switch animation to walking instead of running). Note that it has to be more than -29% of normal running speed, meaning if you or your enemy is on a 100% and become slowed, but the slow doesn't slow down enough to go below -29% normal run speed, then mechanic will still work.

My concern is that on wotlk servers (I play Blackrock the most) it works even if someone has slow effects like crippling poison applied (-70%) going widely below 70% of normal movement speed.

Why do people are still "running" with such slow effects applied on, and then the mechanic is working while slowed down?

Thank you in advance