[smileysteve]

The error in your thinking is that many consultancies are aware of their legal nexus, and actively protect it, so ignorance is not a valid defense for any sensible company.

Talk to people who work for a big consulting firm, they've been taking "tax holidays" for the last 70+ years to ensure they don't spend more than 50% of their time away from their home base.

These companies are no fools; they wouldn't eat productivity and billable hours if they felt the state wouldn't care.

[galangalalgol]

I get that the company wants to know and protect itself. I'm just not sure how they can after reading this article. Short of requiring all employees to check in physically periodically.