After some testing, before allowing Boar Stealing back into Hidden Cup 3 I have noticed the following things.
Boars
Blocking of the boar is always possible with a scout, regardless of who is host of the lobby or whether it is being lured by a vil or scout. This means you can try to force the boar to lose LoS and return to it's original position.
(Remember that boar's share LoS with other gaia units, so be careful when running past wolves/relics/deer/other boar)
Units
Priority seems to be given to the unit that was given the first command, and it is very difficult to block that unit except some minor bumping as it runs alongside.
There also does not seem to be any priority given to the initial 3 villagers over any that spawn later or any other units.
Boars
Blocking of the boar is always possible with a scout, regardless of who is host of the lobby or whether it is being lured by a vil or scout. This means you can try to force the boar to lose LoS and return to it's original position.
(Remember that boar's share LoS with other gaia units, so be careful when running past wolves/relics/deer/other boar)
Units
Priority seems to be given to the unit that was given the first command, and it is very difficult to block that unit except some minor bumping as it runs alongside.
Eg if i start luring a boar with a vil and click under my tc, it is almost impossible for an enemies scout to zig-zag in front of my vil to cause the boar to kill it. But the scout could block the boar to force it to lose line of sight and aggro. But if I click many times under the tc then the scout is able to get me as it has an older command.
This also applies to a villager running away from milita/m@a, do not spam click your vil to tc, make a single click and your opponent will struggle to block you.
There also does not seem to be any priority given to the initial 3 villagers over any that spawn later or any other units.