Re: Naive
Frowned upon and pretty much banned here. Definitely can't be done without first getting the employee's consent and if they don't consent, you can't take any retaliatory actions.
At my employer:
We can't monitor email, for example, without first informing the user. If a user is long-term sick, they are sometimes informed that an out-of-office message will be set and their supervisor will be copied in on email, so that nothing important slips by. (They are also not supposed to use email for private communication, so there is generally no real problems in that area.)
Listening in on/recording telephone conversations has very strict rules in Germany, both sides have to agree, before the recording can take place, there can be no automatic recording. (Warrants for police purposes excepted, but the employer can't spy) The employer has simply deactivated all recording on the telephone and in Teams by policy.
No monitoring software on PCs, smartphones etc. Only the app for clocking on and clocking off for remote workers.
No monitoring of internet access (anti-virus excepted).
In Microsoft 365 all the monitoring tools are deactivated / access removed.
It makes for a much more relaxed and efficient atmosphere (you aren't constantly "looking over your shoulder").