Could be anyone's guess ... I mean, it's going to all speculation (and judgment from the looks of it).
I've had the 'what camera are you using' and even 'what camera is good ah?' type questions thrown at me or even asked nicely before ... even when I was RUSHING to get in position to get a shot. :faint:
When not rushing on downtime, I smile (yes, I try to) and say 'it doesn't matter what camera you use - all modern DSLRs are good, read some reviews and try a few models at the shop and select one you prefer'. I really really don't want to get into the 'this is better lah that is no good lah' as far as possible because there's a lot more objective information out there. I would also be lying if I said I loved to talk about equipment but I understand that some people do, even if they keep trying to force you to talk about equipment.
What I sense is that on the whole, most people who may not be really familiar with DSLRs, or those contemplating a new purchase or first upgrade look to someone shooting on the job as 'THE' person to ask because they assume that such a person is a 'PROFESSIONAL'.
That could be a compliment, or a hinderence as Catchlights pointed out.
If it's a hinderence, as strange as it seems to some, some working pros tend to get irritated - and show it. Imagine you're a engineer and you're up to you sleeves in circuit boards or on a console trying to prevent a reactor from blowing up (figure of speech, please don't take it literally), and the client starts asking you about the brand of screwdrivers you use lah and what soldering iron is good because he wants to mod his remote control bla bla bla, or something as seemingly innocent as a one-question 'Is that a Stanley?'. By then, chances are, you would be distracted.
I'm not saying it's correct to be rude, but do put yourselves in that person's shoes for a moment ... he could just be a sian worker kenar exploited to become photographer, get scolding if the photos are not usable and doesn't get paid at all for the extra responsibility!