> What is the alternative? No security guards?
The alternative is whatever the process is under applicable law for setting, noticing, and enforcing closures on public roads, which pretty much everywhere isn’t “private actors seizing control of public roads and deploying guards on their own decision with no oversight, because the actor thinks that therr might be a safety risk but can’t be bothered following the legal process for dealing with that risk.”
> Yeah no. I'd rather have my legal department battle it out with the authorities.
I suspect if you talked to your legal department first, they could tell you how to deal with it without fighting with authorities and without exposing the firm and individual employees to potential criminal prosecution.
Closing public roads for safety due to construction and other activities occurring on or near them is a regular occurrence for which well-developed processes exist in pretty much every jurisdiction, not some sui generis need that creates a legitimate need to ignore the law because it hasn’t anticipated the need and compliance would be disastrous.