That defeats the point of OP. Anyone just protecting the package should make sure it gets sent somewhere other than the porch. Setting off an alarm means they either run unidentified, grab it anyway tearing it open on way out, or get you back for what you did. All depends on what kind of people were picking it up. The guys in my neighborhood I mentioned here...

https://news.ycombinator.com/item?id=18741738

...were doing what they did in the light walking slowly and calmly between houses even though they knew they were being watched. Your logic assumes the attackers will be afraid of you, the police, or jail. Many down here aren't. They're also vindictive. They're also random where you don't know if you're getting the cowards or hardcore people before the stuff goes down.

So, you have to do strong prevention followed up by being an armed, watchful person with good lighting. And leave nothing of value in your car. They even sometimes steal the alarms. That's because some of our thugs are highly-educated folks that like to show off their brains to their homies during their activities as "self-employed entrepreneurs" as they described it to me. ;)

Because once you start sending secret cameras and gps trackers across jurisdictions for the purpose of catching criminals you really do need a pi license. If your homespun amature detective agency makes a mistake, or gets someone hurt, you better be ready for a multi-year legal headache. Maybe you win out in the end, but it wont be a fun ride.

Every department store security guard knows to never continue the operation beyond the store. Their insurance companies know the potential troubles and wont cover such things.

Good points. It's true there's risk there. I'd have to look up the requirements out here to see what risk. We have less strict rules in the Mid-South on recordings and use of force than in a lot of paces. Might be permissible, might not.