Yes, unmannaged switches can be used to pass audio successfully over Dante Networks. PreSonus Technical Support has found that most off-the-shelf switches under $100 have a feature called Energy Efficent Ethernet (EEE+). Audinate explicitly recommends against using switches with this feature where it can not be disabled, as noted on their website. In some cases, even unmanaged switches may have a method to turn the EEE+ feature off, and while this may work, it is still best to test the switch thoroughly before committing to using it in your production setup.
PreSonus Audio highly suggests always using Managed Switches, so that features like EEE+ can be disabled, and features such as QoS (Quality of Service) can be enabled and configured as needed. For more information, please see Audinate's Networking FAQ's or proceed to this website for specific values of DSCP for QoS in Managed networks.
More information on Dante Networking can be found on the PreSonus Knowledge Base.