Ron Washington once paid a fine with 20,000 pennies

At Spring Training three years ago, Rangers manager Ron Washington was ejected from a game for arguing with an umpire and, in his words, saying "something I shouldn't have said." He also didn't leave the dugout after his ejection, which led to a $200 fine.
That wouldn't be too notable today, except for the news of how Wash went about paying the fine. Apparently, MLB received a box containing the $200 entirely in the form of pennies. Adding to Washington's expenses were the $45 it took to get all that copper-plated zinc to New York via mail.
So, why exactly did he pay this way? Was it a form of protest? Some kind of commentary on the fact that yearly penny production costs $55 million more than the coins' face value? All we have to go on is Wash's explanation: "I didn't have my checkbook."
h/t: Hardball Talk via Fort Worth Star-Telegram