Although many agents give advice, at least one used Twitter to disagree with a player. Reynolds recently voiced his disapproval of New York Rangers star Sean Avery's involvement in a television ad that supported same-sex marriage.
He tweeted: "Legal or not, it will always be wrong."
Reynolds came under fire, as did his Uptown Sports Agency, which he runs with his father, Don. Reynolds tried to clarify, but it worsened when Don essentially compared gay marriage to a marriage between man and horse.
One can tweet too personally. A man accused of stalking tennis star Serena Williams was arrested outside her home this month, with police saying he found her house through Twitter.
One can also tweet too crudely. Tennis player Donald Young fired off expletive-laced tweets aimed at the U.S. Tennis Association last month over what he deemed poor treatment. Young hasn't tweeted since.
But to be on the safe side, should issues such as sex, race, religion or politics be off-limits?
Kathleen Hessert, a social-media consultant who helped launch Shaquille O'Neal's Twitter account, said no, because followers could find a person's account to be inauthentic. Grabowski said yes, because of how much is at stake.
"You have to lay out some ground rules," he said.
The question of taste could be one facing mixed martial arts fighters after the UFC announced a contest in which more than 300 fighters will compete to gain the most followers, for the largest increase in followers by percentage and for the most creative campaign, with winners earning $5,000 every three months.
Regardless of what someone posts on Twitter, though, Hessert said claiming naivete is inexcusable.
"You have to be blind, deaf and dumb to use that argument right now and think anyone would believe it," she said.
But mistakes will still be made.
What could slow them and make some stop and think?
"It's going to take harsh lessons that result in lost revenue," Grabowski said. "A number of people have to be ruined."