Those waste workers shouldn't get a tip, but they should get a share of the winnings because they were the ones who helped find the lottery ticket. If the waste workers hadn't been lucky enough to find the lottery ticket, I think that man would have spent more time and perhaps more effort trying to find it, and there's no guarantee that the ticket would ever be found. He should be grateful to those waste workers for being enthusiastic and kind enough to help him find that lottery ticket.
I don't agree with you because this is looking like entitlement and it's bad. The guy won his tickets and the refuse workers did their job by trashing it, he needed their help to help recover the ticket from the dump which they deliver, if there is anything he can do is to pay them their money and if he looks at the way they help him, then he should have them compensated for helping him out but giving them a share is not the right thing, that's like asking for more.
Let's assume he decided to give them some shares from the money, that's a kind thing to do, it will be appreciative of him to give that kind of gesture but if the waste management ask for shares then they are not doing the right thing. The best they can do from their side is to ask for their money, they'd their right but if they get paid some shares, it's also a reserved money because they helped the ticket guy.