Might be a valid approach if your purpose is to determine who the deliberate repeat offenders are so you can focus your efforts on those who aren't: those who simply forgot the date (careless, but forgivable) and those who don't know any better (new hires, corporate, military, regionals who don't get the unspoken 'Do's and Don'ts'). Costly lawsuits prohibit unions from communicating anything that could be perceived as job action so the uninitiated often end up learning the hard way via public shaming on an open forum. Those who stay off forums may still be unaware so another approach might involve giving the benefit of doubt and personally reaching out to educate and encourage. In doing so, you may find the majority were unintentional and instead of creating a subset of resentful anti-union members, you may get an ally at a time you will need it the most (pickets, TA ratification, strike authorization vote, etc).

Negotiating an industry-leading contract is tough, but even tougher without the appearance of seamless unity. Given management's appetite for division, public forums are probably not the best avenue to air differences.

JMHO