Hills can correct me if I am wrong, but Maine had a similar issue and legislation added a limit on the daily quantity that can redeemed by each customer trying to deter interstate imports (high volume).

About Arizona and California, I recall that some people (can't remember who) posted here that some Phoenix scrap yards had different prices: one for flat or damaged cans and a higher one for clean UBC? Never heard something similar elsewhere. By the way, the other state without bottle return system who's next to California, Nevada, doesn't seem to have the same level of fraud. If they carry cans from Phoenix, I am surprised that no one was caught doing the same from Las Vegas or Reno. It always seems to be coming from Arizona.