You are absolutely correct. However, representatives are not idiots and I think that it's likely that they will be aware, just like you are, that despite the incredible number of faxes/calls/emails they receive the number of people who actually care are likely to be only hundredths of a percent. Since it is unlikely that the politician will lose an election due to hundredths of a percent of a drop in their ratings, you can bet they will just turn their phones off for a few days rather than actually changing their political stance.
Keep in mind a company like Fox or Universal is in a position to offer them what amounts to free commercials on their networks. That is what this potential black out is competing against.
Update: I was unaware of this rule: http://en.wikipedia.org/wiki/Equal-time_rule. However, studios could still offer things like interviews for candidates that it doesn't offer to other candidates, which may not exactly be a commercial, but would have a similar effect.
Keep in mind a company like Fox or Universal is in a position to offer them what amounts to free commercials on their networks. That is what this potential black out is competing against.
Update: I was unaware of this rule: http://en.wikipedia.org/wiki/Equal-time_rule. However, studios could still offer things like interviews for candidates that it doesn't offer to other candidates, which may not exactly be a commercial, but would have a similar effect.