For broadcasters, turning down an interview with a candidate is anathema to a news culture trained to pursue maximum access. Yet the starkly different strategies of the candidates are straining the industry's bedrock notions of evenhandedness.
This is not an ethics question. If one guy speaks a lot, and the other guy speaks less, don't try to cover them both in the same amount. Try to cover them as they say something newsworthy/interesting/valuable. The world is not only not fair, it isn't even-handed. When John F. Kennedy runs against Richard Nixon, Kennedy is handsomer, funnier and quicker and gets more coverage, even if Nixon is at least as substantive and intelligent.
News organizations are selling the news and their reputation for honesty. If imbalance of coverage occurs and might make them look biased because of the way candidates behave and push their campaigns, [then] the organizations have to adapt and talk about it. The world gives them a lot of opportunity to talk about it. It's part of the news of the campaign.