Teach me about people who hand out flyers and coupons

Living in a neighbourhood with a lot of pedestrian traffic, I see a lot of people standing on the sidewalk handing out flyers and/or coupons.

My natural inclination is to politely decline anything I'm not in the market for.  But it occurred to me in the shower that I might be making their job harder, depending on how they are incentivized and/or rewarded by their employers.

Are they incentivized to get rid of all their flyers, or are they incentivized to have a high conversion rate?  If they have to stand out in the cold until they get rid of all their flyers, or if their employer looks more positively upon them for handing out more flyers, I'm doing them a kindness by taking a flyer regardless of whether I'm in the market for what they're selling. But if they're incentivized based on conversion rate, i.e. their employer looks more positive upon them for people actually coming into the business and buying something after receiving a flyer/coupon, I should keep rejecting things I have no intention of using.

Anyone know which approach would be the kindest to the people in this thankless job?