Just a follow-up to Tuesday night's item about the CNBC report which bemoaned the fact that those poor television networks were going to lose millions of dollars in ad revenue because they had to air Obama's primetime press conference.

We already noted the absurdity of throwing a pity party for TV execs who last night simply had to perform a rare public function in exchange for free use of the public airwaves. But the whole TV-lost-millions-in-revenue premise is also annoying because it's pure fantasy. And because CNBC played its viewers for rubes.

Its report suggested that because the nets had to televise Obama, they couldn't air the TV commercials that had already been purchased for that one-hour time slot. And technically, that's accurate. But the notion that networks automatically lost that ad money just isn't true. That's not how the business works because television advertising is not a zero sum game.

Combined, networks control more than one hundred hours of primetime programming each week. Obviously, if some ads get bumped for breaking news (i.e. a White House press conference), networks have the ability to air a those handful of lost ad slots on other programs, just as networks have done for decades. Think about it. Do you really think that when networks break into programming for hurricane coverage, or whatever, that the next day their ad salesmen start writing checks to Procter & Gamble and Budweiser and State Farm because their ads didn't run the previous day? That's simply not how the television business functions.

Networks do sometimes, very reluctantly, hand out free spots to* advertisers if the nets' entertainment programming, over many weeks and months, fails to live up to the ratings rate that the commercials were purchased on. (They're called make goods.) And in that case, yes, nets can lose millions in advertising. But to suggest, as CNBC did, that because of a single White House presser, the networks automatically lost every ad dollar from the commercials that didn't run last night is pretty misleading.

*Changed original wording to reflect point raised by reader.