I think the problem lies with the prosecuters a lot of the time. In UK a person in breach of an ASBO can be imprisoned at once. Recently a charming yoof was on his 15th breach of conditions before being jailed, gaining much street cred with his mates as they saw how powerless or unwilling people were to enforce the law and/or his ASBO conditions. Link here
http://tinyurl.com/3c2hmd