I know that eventually the answer is "whatever I want" but I would like to hear what others think.
There's an MCT oil rig on Baltic Sea. Anarchists from Kronstadt noticed peculiar data transfer some time ago going there and managed to hijack the place. Then they transmitted message that they are an eco terrorist group (I did not specify which one to my players) and demand MCT to stop polluting. After that, folded the satellite dish to buy some time for the decker and rigger to look around the host.
Now, from a point of, for example, TerraFist. An oil rig nearby is in disarray, none of their contacts in other groups say they're doing it. And MCT HTR is definitely on its way.
Does it make sense for them to come to the rig and make contact/make sure it gets disabled/make trouble for HTR?
I think their appearance has potential to turn this job into a nice chaotic clusterfuck and opportunity to show my players some variety of the world (they would definitely come on a yacht going superspeed with help of a spirit).
But does it make any sense at all for anyone besides me?
Committing forces to someone elses operation is risky, especially if you don't have contact with whoever is already on site. In the Shadowrun world there is a real risk that the force attacking the platform is not ideologically allied and is in fact one of MCT's competitors, or even MTC itself trying to manufacture an excuse to strike ecoterrorist assets.
If you want them involved however involve them. They don't have to be perfectly paranoid, or unwilling to exploit the situation, maybe sending another spirit ahead to make contact. They could even have had their own op already past the go point, storming the platform from the sea faster than the HTR could have got there, then bring in the HTR via the air to make things more interesting.
I haven't considered the "you don't know who you are messing with" angle. Good point
Well, from shadowhelix and a few books I understood that eco-terrorists in Europe might-or-might-not have connections to Sea Dragon. So I was thinking about sending them a Saltwater Serpent