I agree on one point only
Omni-Tek is incredibly un-disciplined! Omni-Tek employees are often doing things that they're not supposed to or allowed to out in areas they shouldn't be in without a good excuse.
((OOC: I honestly believe the game should impose some restrictions on what Omni-Tek staff can do. As you said, Omni-Tek is the corporate oppressor, and the Clans are the 'freedom to arm bears' people.))
Other than that, Omni-Tek isn't in breach of the Tir Accord any more or less so than the Clans.
Part of the point of the Tir Accord was to recognise the authority of the Council of Truth. If you're a clanner and respect that authority then you're fine. If you don't, then you're not. Clans aren't a single organisation, true. But the Council of Truth is required to hand over criminals to Omni-Tek for justice. Any clan member who is visiting 2ho constantly should be hunted on both sides of the fence. They aren't, so obviously the Clans need some help from Omni-Tek in policing their own.
As for neutral status, Omni-Tek has always left the neutral communities on the whole alone. So there's lots of Omni-Tek people in Newland? So what? They're allowed to be there. There's often lots of Omni-Tek people in Borealis and Last Ditch as well, and last time I was in Harry's or 20k you couldn't drop a pin without hitting an Omni-Tek employee. There are even small neutral communities right on the doorstep of Omni-1 (the community around the Relax! bar is neutral) and maybe it's just me but I've never seen the guards getting shot in most of these places. The guards in Omni-1 Entertainment seem to come under more fire than the neutral guards in Harry's.
Newland *was* Clan. Now it's neutral. So sayeth the Tir Accord.