With regard to deposit scams, the system we have in the UK works pretty well - the landlord must put the deposit in a government-approved escrow scheme, which then decides any disputes over how much of the deposit should be held back (anecdotally quite fairly).
If the landlord fails to protect your deposit, and does so in what might be considered bad faith, a court will often order them to pay you 3x the deposit as compensation - so they all end up actually doing it.