Possibly, but so far, I have had positive results using them (over a year). You also have to block all entries (cracks in the house foundation too) with steel wool. I use them in a pantry and under my car hood and the trunk.

The noise and the blinking lights act as a deterrent.

My mechanic tells me that they do work as a deterrent in conjunction with other methods. However, after a while the mice can get used to the sounds and lights and ignore them. So, I change the location from time to time.