Subject: It probably depends.
Author:
Posted on: 2014-12-03 12:49:00 UTC
Obviously if, say, the Guardsman found an excuse to actively monitor a Dalek agent, they'd wire a mike into the Dalek's travel machine in the same way as they wired one into the Key. For an agent without any mechanical add-ons to conveniently hold it... well, alternate timeline Constance speculated once about bugs under the flash patches, so that's a possibility. Or just, y'know, keeping an eye on them in general.
It's important to remember that Selene is an incredibly biased observer here. She's had previous bad experiences with the DIA, and is convinced to the point of paranoia that they're out to get her. Whether they're actually prejudiced against vampires is an open question.
hS