Funny story
Don is correct. If they want in, they'll get in. Simple idea is to have a light or radio inside on a timer. It implies that someone is home. My dock neighbor (live aboard) on a trawler put a motion light up high so that when someone walks down to the end of the finger of the dock it lights up the world for 2 min. Whenever I'm over staying onboard he turns it off for me.
A number of years ago, a guy at our yacht club had a motion sensing light on his dock.
So, whenever anyone walked down the dock to his boat, a very bright light lit up, not just his, but the adjacent neighbour's boat.
Well, this was a bit of a problem for the neighbour insofar that when he went down to his boat late at night, it made the the area very visible.
Normally, this is a very good thing;
Unless of course the person accompanying you on board doesn't look exactly like your wife.
So, rather than asking his neighbour to get rid if the light , ( for obvious embarrassing reasons), he would "disable it" with a baseball bat.
So, every week this guy would patch up his light & replace the bulb, only to find it smashed to bits after the weekend.