I have always wondered what quality of advice do defense lawyers really give their clients. The quality is very important when it becomes relevant for post-sentencing issues, such as immigration status, ability to find a job, or sit on the board of directors of a coproration. Tont Mauro previews a relevant case in front of the US Supreme Court. In the US, the consequences may be:
Depending on the offense, a guilty plea or verdict can, in addition to the penalty for the crime, also make it impossible for a defendant to vote, live in public housing, become a cosmetologist, carry a gun, drive a car or receive a growing array of government benefits. If you plead guilty to public urination or if, as a 19-year-old boy, you had a relationship with a 16-year-old girl, you can in some states be marked as a sex offender for life.
Of course, what is assumed here is that the defendant would have been found not guilty had they plead not guilty and fought the case, based on the proper advice. In my very limited experience, defendants look to their lawyers for the best advice they can get, even if that means pleading guilty.