Do the wrong thing? Open your mouth at the wrong time? There is a price to pay. I was curious and found these examples of what it costs to pay the piper.

Kobe Bryant
Sponsor: McDonald's
Lost sponsorship because: Charged with sexual assault
Nutella chocolate spread, also decided to abandon their endorsement deal. Coca-Cola soon followed them, pulling their Sprite ads that featured Bryant. An Associated Press report suggested that Bryant lost between $4 million and $6 million in endorsement

Latrell Sprewell
Sponsor: Converse
Lost sponsorship because: Choked his coach
this endorsement contract was worth between $500,000 and $700,000 a year.
Warriors responded by terminating the remaining three years of Spree's four-year, $32 million contract.

Martina Hingis
Sponsor: Sergio Tacchini
Lost sponsorship because: Badmouthed company merchandise
a five-year, $5.6 million sponsorship deal

O.J. Simpson
Sponsor: Hertz
Lost sponsorship because: Charged with double murder
Simpson was totaling as much as $2.5 million a year from his Hertz commercials, his NFL commentary work for NBC and his appearances in the Naked Gun movie series.

Earvin "Magic" Johnson
Sponsor: Converse, Pepsi
Lost sponsorship because: Contracted HIV
His endorsement contracts were worth a total of nearly $12 million.

Barry Bonds
Sponsors: MasterCard, Charles Schwab, KFC
Value: Part of annual endorsement income of about $4 million
Why the deal went sour: Steroid scandal

Bode Miller
Sponsor: Barilla
Value: Part of his yearly endorsement income of about $4 million
Why the deal went sour: Outspoken party animal who failed to deliver the goods

Jason Giambi
Sponsors: Pepsi, Arm & Hammer, Nike
Value: Around $3 million per year
Why the deal went sour: Steroid scandal

Dennis Rodman
Sponsor: Converse
Value: $15 million
Why the deal went sour: Outlandish behavior

(thanks to Branddunk.com and Askmen.com)