The .htaccess rules do not block access to these folders unless they actually exist. When they do not exist, the SEF URL section kicks in and asks Joomla! to handle that URL which triggers a 404 error in Joomla!. That's why we have the 404Shield.
As to blocking access, I do not think it is ever appropriate or desirable to forever block an IP address (which might be a dynamic IP address, mind you!) if there is one and only one errant request. The whole point of blocking the request and recording the blocked request is that repeat offenses from the same IP address will lead to that IP address being temporarily blocked. If the same IP address gets temporarily blocked too many times then and only then does it get permanently blocked. In other words, Admin Tools implements proportional escalation.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!