The case is Aversa v. UCBR, and it's a Pennsylvania Commonwealth Court case reviewing the decision of the Unemployment Compensation Board of Review (UCBR). The UC claimant was a salesman who lost part of his region to a co-worker. The Claimant emailed the co-worker a spreadsheet with sales figures from the region, and the body of the email read:
Ohhhh, not just "I won't forget it" - but, "I WON"T FORGET IT" all caps style! The employer terminated the employee for making a "threat."
The Court sided with the Claimant. The Court held that there was no threat of actual consequences, just an admonition that the Claimant would not forget what the co-worker had done. The all caps added emphasis, "but it did not transform a four-word declarative sentence into a threat of violence." The Court also provided some interesting analysis specific to emails. For example, "[a] message transmitted through cyberspace does not contain the same force or immediacy of an in-person exchange; it is absent of voice or hand gesture." And, "[n]otably, the type size used in the e-mail is much smaller than the type size used in this opinion."
So, when assessing workplace threats via email for UC purposes: (1) email is not as threatening as in-person confrontation; (2) font size matters (really?); and ALL CAPS may add some emphasis, but is not in itself threatening.