There's no law against issuing a PR without the disclaimer, but the "safe harbor" language is meant to warn investors of "forward looking statements."
For instance, if I issued a PR for my investors stating, "We opened a checking account at Citibank with $250 and they provided an ATM card," that's a fact that doesn't need to be qualified as a forward looking statement.
If I issued a PR saying, "We applied to Citibank for a loan and we anticipate it will be approved." That's a forward looking statement and I better have placed a disclaimer on it in case the loan isn't approved.