As he is a courier he's in a better position to advise on the realities of the job, surely? His opinion may not be more 'valid' but it is probably more accurate,
What if the guy asking has no knowledge of London and is actually a bit scared of traffic and bendy buses and is allergic to rain and can't fix a puncture or read a map?
What if the guy asking has no knowledge of London and is actually a bit scared of traffic and bendy buses and is allergic to rain and can't fix a puncture or read a map?