Ok, So I did the following by using the "All Devices" option.

I have my wired management PC, Android pad and iPhone. Both had the MAC address randomizer enabled for this test.

Check mark the devices that you seen that need to be controlled. Be sure to leave your management PC (green star) and any allowed or authorized devices un-checked so you don't block these.

After you have the selected devices checked to be blocked, select the BLOCK button, then select the APPLY button.

The status should change to BLOCKED on this page.

I checked my two test devices and though they were connected to the signal, they had ZERO internet access. I check this by trying to access the CBRs web page on both and could not get to the CBRs page. Even when I configured the faux AP mode on the CBR and connected behind my main host router. The one PC had internet, the two wireless devices did not.

So this should work. NOTE: Only thing is you'll need to keep an eye on this page and look for any new devices online when they appear, if you see something new and you think its the childs device, follow the process and block it. You'll need to keep and eye on the the MAC addresses as well, the MAC address randomizers will change the MAC address so you may see same devices appear with different MAC addresses in the list.

I recommend you make a list of authorized and known MAC addresses, I'd set these devices with MAC address randomizers to OFF while at home. Then make a screen capture of the access controls page. So you know what devices are allowed and authorized. Then start making changes to the ones that needs to be blocked that appear on the controls page.

When devices need to change from block to allow, Just do the same thing by checking the device, then select the ALLOW button, the the APPLY button.

This process seems to work though maybe not smooth or efficient. You'll need to keep an eye on this page and what the child is connecting. Should gain you some controls here.

Good Luck.

Any plans of enabling DEVICE VIEW on the GS110tp like you have done on the GS748Tv5 model PLEASE?