I am not a people leader, but have gone through several layoffs, and know first hand how it went with colleagues and friends that were impacted. Generally, meeting requests went out the morning of, with very little notice. Exception is if your manager and you are both onsite at the same location, then they would come over and take you to their offcie or conference room, and you may not get an invite at all - this was prepandemic.
But I think certain groups and depending on your role, may have different risk levels regarding why they want to wait till the last minute. If you were in ops and had elevated privilledges to production systems, then they definitely dont want to give you any heads up. But for majority of folks, this risk is low for many reasons.
In the past I have never heard of anyone impacted getting advance notice through suspicious invites that come in on a Friday, or over the weekend. This is just my experience. and what I have observed. They could do things differently this time, since this is the only major layoff we have had (3000+) while most are WFH.
This is good info from @hyb+1pkfG1ks, reposting it so more people see it.