What is the difference between validation and inspection?

Validation:

Validation is a check of the validity of a ticket in time and place. The result of a validation is either positive or negative. A positive validation result will confirm that the ticket is used at the right place, geography and/or vehicle type etc, at the right time. A negative validation result will indicate that the ticket is not valid for the place and/or time. A negative validation result can be handled in many ways depending on the business rules of the PTA/traffic company.

Validation can be done by different devices such as bus validators, handheld units, gates or platform validators. A validation may also activate a ticket or payment procedure. 

Inspection:

Inspection is a check of the validity of a ticket. If the ticket is found to be invalid, a fine could be issued. Inspection is typically handled by dedicated staff that are apart from bus drivers or train hosts.