Marching someone out the door...
...might not be strictly legal in the UK in the case of redundancy. Government advice on redundancy:
You’re entitled to a consultation with your employer if you’re being made redundant.
This involves speaking to them about:
- why you’re being made redundant
- any alternatives to redundancy
You can make a claim to an employment tribunal if your employer doesn’t consult properly, eg if they start late, don’t consult properly or don’t consult at all.
Alternatives to redundancy can include applying for other jobs within the organisation, if these are predominantly posted online then revoking all network access for the employee can be difficult.
Of course you can still revoke access to critical systems and if they've been fired then none of this applies. Ditto I suspect in the USA.