Hey AGO, Connor here from Meraki Support.
It's not a hard limit as far as I'm aware, we simply include these figures as this is a recommended number of clients before you start to experience reduced throughput due to CPU/Device limitations. Each device connected either locally or remotely regardless of if it's only using a small amount of traffic adds additional load to the device's internals.
Kind regards,
--
Connor Loughlin
Network Support Engineer
.:|:.:|:. Cisco Meraki EMEAR 🇬🇧
For reference, many questions can be easily answered by searching our online documentation: http://documentation.meraki.com