Why would executives pay any attention to laws when nothing very bad ever happens to them for not doing so?

Comcast Corp. CEO Brian Roberts will pay a $500,000 civil penalty for failing to report under Hart-Scott-Rodino antitrust rules 338,000 Comcast shares he acquired through his compensation package and 401(k) plan.

The Federal Trade Commission and U.S. Justice Department said on Friday that Roberts’ neglecting to inform them of his additional Comcast stock ownership between 2007 and 2009 was a mistake. They said it was the apparent result of bad outside legal advice, but it also was the CEO’s third violation – though the previous two did not lead to fines.

The agencies disclosed the civil penalty on Friday. Roberts was not fined in 1999 and 2000 for violations related to the Internet Capital Group Inc. and Susquehanna Cable transactions.

“He had his free bite at the apple but he did it again,” said Barry Reingold, antitrust partner at Perkins Coie L.L.P. in Washington.

Reingold said he believed the penalty was modest because Roberts faced fines of between $11,000 and $16,000 a day for continuous violations over almost two years – which could have amounted to several million dollars, based on the government’s description of the maximum daily levies.