High frequency ultrasound vs scorpions

My girlfriend pointed out that we have 2 high frequency emitters in the kitchen in a direct line of site to the scorpion cage.  This is because roaches were a problem at my last address.

I've since unplugged them and noticed some increased activity from my scorpion.  Is this by chance?  I also noticed increased interest in the cricket but not actual feeding as of yet.

I have never used one of these devices, but I had a bit of a search for information about them.

There's mixed opinions on whether they are even effective at deterring anything, however, there are some references to the devices repelling arachnids, so as a precaution I wouldn't use them.