EDIT: After my semi-long post I re-read your question. Yeast as you know are affected by temperature or by how many of them have dropped to the bottom of a fermenter and gone to sleep. Repositioning a fermenter can jostle up the yeast enough to be resuspended into the food they love eating and get them to start fermenting again, and an increase in temp changes can make lethargic yeast wake up again and start eating, or if a fermenter is moved CO2 can just come out of solution and produce some airlock activity. Gravity readings, I believe are the only way to tell if 1. Fermentation is taking place. 2. Fermentation is complete.
I once fermented with a 10g Rubbermaid cooler lid covering a 6g bucket because my nearly airtight fermenter bucket lid was not to be found. There were no reassuring little glub-glubs coming from an airlock, no hiss coming from the very loose fitting lid.
On day three I checked gravity and fermentation was certainly happening, on day six and seven I took gravity readingd and it was at final.
Left the bucket sitting that way another 3 weeks and then replaced the Rubbermaid lid with saran wrap. (the lid wouldn’t fit into the temp controlled freezer) crash cooled it for another 3 weeks (mainly out of laziness after the first week of cold crashing) at 30 degrees and the Beer turned out just fine, clear, no off flavors and it is yummy!
I'm forcing myself to be patient, use great sanitation, and not worry about the brew so much. Take care of the yeast and they take care of the brew, they know what they are doing .
Sanitation, temp control and patience are probably the most important three ingredients to making beer.
Fresh ingredients are at the top list as well.