From Reid’s experience, people who think they are being bugged usually check for wires, spy devices, and other related equipment in objects located in plainer sight. Without trouble, he can recall dozens of films where people look inside light bulbs, mirrors, fishbowls even…
The reality of spy devices today is - most of them are wireless. Blame the internet age, but unless one needs to keep up long-term surveillance over someone, it is just easier to set up something that runs on a battery and can be hidden more easily.
This is exactly what Reid is doing right now.
Of course, if Sandra or whoever is with her suspects they are being listened in on, they can track down the bug with an appropriate device (really, even FM radios work for that, since it’s all radiowaves), but Reid doesn’t intend to keep this up long enough for this to happen.
And of course, it’s better to hide the bugs in places no one would expect to look for one. Like behind their kitchen counter. After all, when was the last time someone decided to clean behind there?
Or way behind their toilet tank?
Or right in the middle of the bottom of their bed? Seriously, if anyone checks down there regularly, thinks Reid, then they have way too much free time on their hands. And the bedroom is always a good place to bug - people say a lot of important information when they think they are in the privacy of their bedroom.