There are invariably allegations of voter fraud, particularly in a close contest such as the Democratic Iowa Caucus. The allegations are made by conservatives, who have questionable motives. No doubt, they would like to bring down the party's front runner. Although there is the presence of an apparent video, these can be easily doctored.
I don't believe that the voter fraud issue in Iowa can be directly tied to the Clinton campaign. While it's clear that Clinton's victory is no longer the sure thing that everyone assumed it would be when she first announced her candidacy, I don't believe that either she or her campaign would condone the explicit use of tactics like this. I think she's smarter than that. She's had enough scandals come out already to know that something like that wouldn't stay a secret
There was no actual evidence of voter fraud in the Iowa caucuses. To understand how it works, a person must know the rules. People go to their local precinct meeting place and split into groups. Candidates with too few supporters and the undecided folks must gather information and make a choice between the candidates that are viable. For example, in my precinct, each group had to have at least 15% of the supporters to remain viable. O'Malley and the undeclared groups didn't meet this threshold. These groups then had 30 minutes to walk around and talk with the other groups to make a decision. After the 30 minutes, if they did not choose to join either Clinton's or Sanders' groups, they had to sit out and not be counted at all. Once groups are formed, delegates are awarded based on the final count. In a precinct where there is an odd number of delegates, there has to be a way to break a tie. That is where the coin toss comes in. I have heard many stories about the caucuses in Iowa, but none that were actually against caucus rules. There was no evidence of voter fraud.
I don't think it is fair for the media to accuse the whole Clinton campaign if there has been some voters who tried to cheat the system by getting more votes in. Only if we have proof of them organising is the way to accuse them, not only by independant cheaters.