How to block a customer from ordering

Hi,

If you want to disable the whole website for that IP address, you can easily do so with an extension www.akeeba.com/documentation/admin-tools/waf-ip-blacklist.html or with some rules in your website's .htaccess htaccessbook.com/block-ip-address/
There is no option to block guest checkout itself only for some IP address / email address. It would be possible with the development of a small plugin but that seems kind of overkill.
One other alternative I could is to use this extension:
www.hikashop.com/marketplace/product/250...shipping-plugin.html supposing you don't already use USPS/Fedex/UPS etc shipping plugins so that instead of manual shipping methods, you would configure geocoding shipping methods in the same way, but with a restriction for a radius of a kilometer around the exact shipping address of that customer so that if someone would enter an address there, no shipping methods would be available to him on the checkout.
But again, that seems quite convoluted compared to just blocking the IP address on the whole website in your htaccess.