This is only the first half of the option you have to set.
config user group
edit <name of your guestuser group>
set auth-concurrent-value 1
The description is:
Set the number of concurrent logins permitted from the same IP address. Range 1 to 100. 0 means no limit. This field is available if auth-concurrentoverride is enabled.
What makes me wonder is the part talking about " from the same IP address" . Typically, a hotel guest will bring in 2+ devices which connect on the open WLAN, each receiving a unique IP address from the DHCP pool. That would mean that this option will have no effect. I' m afraid you will have to try it out yourself.
"Kernel panic: Aiee, killing interrupt handler!"