I think the ruling class has solved this problem, just as it has figured out how to solve the problem of the use of liberal rights and democratic procedures by the lower orders. As Chuck0 notes, any action which does not cause material problems for a lot of people will now be ignored. In any case, anarchists can't depend on the immediate appeal of unions and Civil Rights (and the anti-war movement) because these simply asked for liberal rights within a nominally liberal system. That is, people were demanding what they had been taught was theirs and good in grade school. That made it possible to quickly get large numbers of people at least loosely organized into demonstrations and voting blocs before the bourgeois media could get to work on them. The fact that the union, Civil Rights and anti-war movements did not subsequently develop into a militant socialist or communist movement shows their basically limited, liberal nature; they dispersed or became conservative when their immediate goals had been achieved. There was no fundamental difference between what they were asking for and the way liberal capitalism was supposed to work anyway. We (radicals, that is) can learn from these movements how to temporarily divert or stymie the established order, and possibly even inspire moderate, usually transitory reforms, but we don't observe an example of more than that.
However, like those liberal-reformist mass movements, mere vandalism and street theater do not replace existing coercive and State-dominated relations and institutions with anything else. In this sense they are distinctly limited and probably not worth carrying on about one way or the other.
Suggestions for a more effective _radical_ praxis might be interesting, however.