Blocked device gets unblocked

 I am pretty sure they do not have access. This also happens on my sons Chromecast. The chromecast gets unblocked almost imeadiatly, faster than he could even log on if he was even able to. I never use the default password, this is the first thing I change. I would also change the user name from admin but it doesn't allow it. I can change the password again for a test to see what happens. I highy doubt they have access. I run genie on my phone, my PC and my wifes phone. I'll try doing some test to see I can replicate the problem. Is it possible that resetting the wifi connection would do this?

Thanks for your help