To me, alarms area nusiance. Especially when the person is not even around to turn it off. There is a reason why municipalities are charging homeowners for nusiance alarm calls.
1) Someone else probably has the key to your camper already, unless you have changed the locks. This goes for the door and the common CH751 bay doors.
2) If your next to me and your alarm goes off because of your dogs or any other reason, and you are nowhere to be found, you will probably come back to removed or cut battery wires and your RV unplugged from power. Hopefully it won't get too hot or cold for your dogs inside.
3) Don't take anything of value with you camping. If there is a concern, take it with you, when you leave.
As others stated, we've only had a cooler taken from underneath our old TT once. It had beer in it and the cooler was found that morning in the dunes at teh beach, minus the beer. Our unlocked Cannondale mountain bikes were sitting 10 feet from teh cooler and were not touched. If I felt concerned, I would just lock up everything, not leave the campsite at all or go elsewhere. Rving is about relaxing. RVing in fear is not relaxing.