Dumpster Divers

I live in an apartment complex in Citrus Heights and I see people who are not residents, dumpster diving at least once a week usually in the morning or late evening. There was a couple who would ride up on bikes with little trailors hooked up to them and go thru the dumpsters, loading up their trailors. Then they'd move on to the next dumpster. There has also been many storage units in this complex broken into in the last year. Locks cut. I'm curious to know if anyone else has seen dumpster divers in their complex. After my storage was broken into, I did wonder to myself if these divers had anything to do with it. Should this be allowed? I really don't know. I'm thinking it shouldn't be OK.