If his supporters actually cared about any of this it would make an impact. But him doing business across an unjust embargo isn't really going to rattle anyone
Since I don't support trade embargoes, even against loathsome regimes like that of the Castros, it would be hypocritical to call out Donald Trump for circumventing it, if in fact he did. It does highlight a sensibility that the rules don't apply to him, though. Although, Chelsea Clinton taking a private jet to a climate change roundtable that was only a five hour drive away also demonstrates that.
While it's probably true that most people won't much care, the Cuban-American voters in Florida, an important battleground state in this election will very much care. This is why he has made a point of going to Florida and talking to Cuban-Americans, a key voting demographic in Florida, specifically telling them that he believed in the embargo and would never do business with Castro/Cuba. So they may very much care about this news as well as the fact that he lied to their faces about it.
Donald Trump - Miami Herald - 1999: Donald J. Trump: A choice for human rights WaPo - 1999: Washingtonpost.com: Cuba Special Report The "We Are All Socialists Now" Newsweek article was a tad slanted.
Ever hear from Cuban-Americans on what they think of the glorious wonder woman ex-beauty contestant voter goddess Clinton used to "score points" against Trump during the debate? Seems they have opinions on everything in that community.
Newsweek was hit by a DDoS attack after publishing the Trump story. They claim the computers involved in the attack mainly had Russian IP addresses. Newsweek suspects hackers crashed website because of negative Trump article- POLITICO Media