Knocking on command

Heres an interesting one too me because while I was randomly recording on my cellphone, I asked if someone was around, and if they’d make a knocking sound. And while I didn’t “physically” hear the knocks, it seems an odd coincidence that it would happen 3 times on 2 different videos.
The reason I asked for proof it wasn’t contraction or expansion (despite not physically hearing it) is because, this is a metal roof and it will make noises on occasion.
But again, I find it strangely odd i did not hear it in real time and the knocks came after asking.