When It's Okay to Mix Past and Present Tenses

When It's Okay to Mix Past and Present Tenses

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This is an example, which I made up, of how present and past tenses can be used in the same article for rhetorical purposes; that is, to best present the material. The legal statements are not factual; I made them up for the occasion:

A man gets on a bus. He finds he doesn't have enough change to pay his fare. An argument ensues and the driver insists the man get off the bus. The man becomes irate with the driver and they struggle on the bus. The man sustains an injury to his wrist and sues the bus company. Who was at fault?
    According to the law, a person who is asked by a county employee to remove himself from a public vehicle must comply with the order to do. If there has been a violation of his rights, he has the recourse to legal redress at a later date.  But he cannot defy an order to remove himself from the vehicle.
    Therefore the man who boarded the bus is not entitled to legal damages for his wrist injury, etc.

This is correct because obviously the writer is in control of his material and the reader senses it. But compare with the version below, which poorly mixes tenses:

A man gets on a bus. He found he didn't have enough change to pay his fare. An argument ensues and the driver insisted the man get off the bus. The man became irate with the driver and they struggle on the bus. The man sustained an injury to his wrist and sues the bus company. Who was at fault?
 
Can you see the difference? This mixture of past and present tenses is wrong and confusing, without rhetorical purpose. The purpose of mixing tenses in the first sample was to bring the legal situation close to the reader, as if it were happening in front of the reader's eyes, before switching to the past tense to discuss the legal issues involved.

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