So how many of your non-tech-savvy customers frequent MyBB? I fail to see, that the issuing of a notice about degraded performance will result in mass panic. The purposeful decision by your management team to actively hide such information from the general public is actually more of an issue than being transparent about it. Anyone using Google Apps or AWS services will be familiar with service notices pushed to customers. The only time companies should not disclose information is if this could cause more damage (and this would only apply to what companies did during Heartbleed or similar events, where you would not disclose openly that you are patching servers due to a specific vulnerability).
I honestly don't understand why you could not just post on your public notice board "We are experiencing latency and throughput issues due to overutilisation/bugs/we-dont-know/whateva on our network and our engineers are working on it. Users will experience degraded performance when doing XXX" - can't be that difficult and I am failing to understand how this can result in "mass panic".
So by the sounds of it, very soon we are all getting another soppy mail from Gian - flashback November 2014, after 3 months of not wanting to "blow things out of proportion" -
http://www.fin24.com/Tech/Mobile/Afrihost-apologises-for-network-problems-20141121
I didn't think that I need to explain to your executives the basics about corporate governance and transparency, but wilfully deciding not to disclose issues which result in not providing customers with the agreed service is certainly wrong and unethical. The only reason your executives decided to withhold such information (as in previous cases) was to avoid customer churn (which you faced anyway).