In my last role at a large 6000 user enterprise with proper Cisco network infrastructure this was a definite no no for obvious reasons.
But here, a small 20 user company, does it really matter? Are we making the network potentially slower or not proper CAT6 by doing this? Or as they are unmanged to these little switches just do not much except forward stuff without any logic.
The main switch is a Dell Powerconnect 5524 and we use a Sonicwall NSA220 for internet/firewall/wifi. Scattered around the office are three Dlink DGS108d and 105D 8 port unmanaged switches.