Well, it all comes down to what you do with the recordings and also the intent of the recording.
If your intent is to record for production of a product you will likely need a permit in many places, a filming permit.
If you intent is to use for other reasons (depending on local laws) you dont need a permit, but you cannot use the resultant recording for production/release of any content including audio/written description of the recording without the consent of (depending on local laws) one or all parties in the recording.
Yes, recording anyplace not public just consider that a NO GO zone, keep out of private spaces, even like where a door might open to a private space, be careful on this!!!!!!!!!
But, if you put a camera in a public space (No reasonable expectation of privacy) in most places you can record there for NON releasable content, but if you are going to use it in any way you will need a permit likely and/or releases from the people involved.
Even hidden camera shows have a filming permit, and after the fact get a release from the person in the clip to publish any part of it. Shows like Jackass have tons of non usable footage cause no release was signed, either the people didnt want to, or they left before they got ahold of them.
But, my suggestion is to contact a lawyer in your local area that deals with film production and they can get your the legal interpertation in your area.
Like in canada only one party needs to agree to recording a phone call and it can be releases without the others knowledge, so that is not the case where I am, and likely not where you live.
Bottom line, is if you are going to record anything for any sort of production or even used for other purposes like audio desription of the event or even written you will need to do some serious looking into the laws in your area.
Easiest is just contact a local lawyer that deals with filming and get ther opnion on the situation.