Orrrrrr the ad-blocker would just keep on using the software?
And before someone states how there are scripts to detect ad blockers, think about it for a moment; I'm sure a blog or website with ads would see a decrease of literally about 75% of their readers who would be annoyed to be forced to pay or turn their ad blockers off.
Well, personally I already turn off my adblock in some sites.
And better 75% less readers than 100% of reader who bring no profit because they block the adds