The parade may affect locally, but on a general scale, it won't be effective in solving the whole issue. Gambling addiction is complex, regulations are required to prevent and measure it widely. So only by judging based on a single unknown video, the effectiveness certainly can't be measured precisely.
Affect locally, both positively and negatively imo. Positive effect, the parade may make people aware about the dangerous effect of gambling. Negative effect; the parade is introducing gambling to people who have never knew about it. Coming up to effectivity, it is depending how the parade present it to piblic as well as the level of awareness from the people who watch the parade.
Indeed, one of the unintended consequences is those who haven't been exposed to gambling may be curious about what it is all about. It may lead them to experience and get to know about it. Especially children without direct intervention or guidance from their own parent.
I can't say it won't have any positive effect, but I believe it will be insignificant noting the parade is polished in a fun and ironic way. You know kind of inside jokes from the community, so that is the reason why I have that opinion.