Yes, I feel the webmasters need to add anti-adblock script to their respective websites for the following reasons:
1. As per survey more than 60% internet users use ablock plugin in their browser. This harms the webmaster in terms of the revenue they manage to run the site.
Contradiction: Some people will have no objection to see ads in the sites which they love to be active but by default the adblock plugin disables the ads and people really forget about the adblock being activated. I myself was one such person. GizmoLord was blocked of ads by default and when I was reading a topic related with ads here, I realized that the adblock plugin is activated for GizmoLord and thus thereafter I disabled it here.
So, a short tooltip message at homepage for the adblock plugin users should be displayed and request them politely to disable adblock for the site to support it.
On the other side, webmasters should not integrate more than 2 or 3 ads per page making the site load slow.