Not seeing bubbles in an airlock - Does NOT equal no fermentation - plain and simple.
We see a lot of questions on here about this very thing - typically from first time wine makers or those who mistakenly became 'dependent' on the sight of those bubbles for their sense of security.
That's the reason for my aggressive, 'downing' comments. When new wine makers are mislead on what should be happening, what they should see - it can lead to panic, premature intervention, and loss of confidence in the actions. Since I understand that this site is all about sharing the knowledge and encouraging, I find it very difficult to sit back and watch repeated guidance to folks that make a person worry over nothing or take unnecessary steps. That's the only reason for my comments like this - To prevent fostering a misleading trust in something like the bubbling airlock on a bucket or large mouth container.
I've seen a wine in a glass carboy that is already a .990 and the airlock itself never bubbled even though there was a steady stream of fine bubbles in evidence. I didn't stand around and wait to see if the airlock eventually moved. I did check the airlock fit and moved on.
I've checked on wines that have been aging for several months only to see the airlock sitting there as high as possible, no streams of bubbles or foam or even evidence of wine or foam having entered the airlock. In those cases I clean and refresh the airlock, smell the wine, and maybe lower the level half an inch by taking a small taste sample. Unless something smells or tastes seriously wrong, I move on.
As always, I can be wrong about something and I'm always ready to learn more and/or better ways or more correct methods.