People leaving money behind in trucks? (7)

I believe the answer is:

tippers

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'people' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'money behind in trucks?' is the wordplay.
'money' becomes 'tip' (money given for service).
'behind in trucks?' becomes 'pers' (I can't justify this - if you can you should give a lot more credence to this answer).
'tip'+'pers'='TIPPERS'

'leaving' acts as a link.

Can you help me to learn more?

I've seen this clue in The Times.

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