Maze TD creep Antistuck

For example in BK's Gem TD.
How do creeps know to ignore towers / blink when path is blocked?

If a unit has an attack, the said creeps will go agressive and attack towers if they are blocked. Aka. Skibi TD.

I wouldnt know exactly how anti block done in Gem TD, however you could take advantage of this attacking behaviour and move the creeps whenever they attempt to attack.

What prevents creeps from attacking when they are not blocked?

Having a move order, I assume. Being blocked causes the units to give up on that order and enter idle behaviour, in which they auto-attack nearby enemies, in this case towers.

Ah of course, tnx people.