Is a there a simple solution to avoid problems with hotspots?
From your screenshot it looks like your browser is opening (and later failing to open) a login screen in a new window. Try using a different browser.

You might also try 

System Preferences -> Network -> [with "Wi-Fi" selected] Advanced ->
 uncheck "Remember networks this computer has joined"

and / or

Keychain Access -> [with "System" keychain selected] -> delete the AirPort network password