When you start blockland and it starts loading add-ons, you may notice that that after each add-on name it gives a CRC code. This is a code generated from the content of the script, and I believe it is unique to every possible text file (not entirely sure how it is generated).
Some specific add-ons that have gotten into circulation that Badspot deems to damage play experience or are just cool looking addons that are truly crappy, or like eval that can damage your server, can be banned by CRC code. Those mods are otherwise known as crap-ons.
