on a private house, double cylinder deadbolts are ok, and there are likely to be two or more places to get out. however on a rental property they likely are not code, that makes them a code violation that will be listed when the property is inspected for the rental housing liscence, and the order will come down to change it. if not changed by reinspection some sort of liscence enforcement can be expected. they will give you a month to report it fixed.
Medeco makes a nice double cylinder deadbolt that has a key with a thumbturn bow, so it can be left in most of the time and taken out when thats the level of security you need, such as locking up at night. Use to see them a lot in the security upgrades on that 'it takes a thief' show on the discovery channel.