Should professors who donate to Obama's campaigns note their donations when the media interviews them for comments?

Of course, if reporters asked academics if they have donated to Obama's campaign, it would greatly limit the number of academics that they could talk to about the race.  It isn't really a problem for donations to Republicans because there are very, very few of those (see here, here, here, here, and here).  From The Hill newspaper:

At least a half-dozen professors who gave political donations to President Obama have been quoted in news articles opining about his administration and the 2012 race for the White House. 

The findings of The Hill’s months-long investigation come as Republicans have been crying foul, alleging a media bias for Obama and against Mitt Romney.  

The Hill cross-checked academics who have been quoted in news articles with Obama’s donor list and eliminated those who worked in prior Democratic administrations. The half-dozen professors detailed in this article do not mention their political affiliations in their bios online. A similar search for Romney donors did not yield any results. 

The scholars say they didn’t tell reporters that they had donated to Obama, but would have had they been asked. It is not common practice for journalists to inquire about such political donations, however. 

Kelly McBride of the Poynter Institute says journalists should ask about political contributions: “Reporters are trying to get an independent viewpoint. Increasingly, the audience is demanding to know how [reporters] get information. The audience would like to know this information.” . . .

The Hill then goes through some examples of academics who have commented on the race to major media without it being noted that they were donors to Obama's campaign.