Chicken Feed For Crows?

Corvid Cleaning has advocated a novel approach for removing cigarette butts from Swedish streets (https://www.theguardian.com/environment/2022/feb/01/swedish-crows-pick-up-cigarette-butts-litter). Circa 1 billion cigarette butts are dropped around Sweden each year. These account for 62% of all litter on Swedish streets. The costs of street cleaning are very substantial. For example, the town of Sodertalje near Stockholm spends around £1.6m per annum. The Corvid Cleaning owner intends to train crows in Sodertalje to pick up cigarette butts. When a crow returns with a butt, it will receive a small food reward. Corvid Cleaning estimate that this will reduce the costs of removing cigarette butts by at least 75%. A number of questions remain. Firstly, how will they ensure the crows do not become poisoned by the toxic materials in the butts? Secondly, is there not a danger of some smokers deliberately throwing down their butts, to watch the crows retrieve them? Thirdly, what's to stop these intelligent birds 'fishing' butts out of waste baskets to boost their rewards? Fourthly, will nearby bird feeders disincentivise the work force?