There was a recent post by someone from Australia (I think) that had perp(s) enter his home while he was away. Seemed to have spent a LOT of time entering and searching. They did steal his NVR, but not his cams. If I remember correctly, he did not have SD cards in his cams. Also I am not clear remembering, but I think they somehow disabled his alarm. So he has no video of the burglary.
Personally, I have an alarm and neighbors that know when I am away. They know when I will return. I check my system at least twice a day when I am away. My BI server is not hidden so it could easily be taken. Somehow I doubt that anyone will take my cams and they do have SD cards. There are multiple cams at each entry point and inside my home. If they were to try and take cams, they would need ladders to get some of them. Good luck not attracting any suspicion doing that. Cams, POE switches, modem and BI server are all on separate UPS's. If I were to attempt logging in and could not gain access while away, I would be calling my friends for answers.
Obviously a determined burglar could get through unobserved, but it would take a lot of planning and I am just not that interesting for that much bother. And if they do, I have insurance.
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@Mark_M said, security is in layers.