Oregon Measure 74
Medical Marijuana advocate blocks recreation bill. Claims that recreation bill would somehow make an overabundance of growers and a massive price increase on medical cannabis. The reality is that recreational growers have caused medical cannabis prices to fall and demand for medical cannabis services to fall as they are no longer needed to get around state prohibition. This would have dramatically impacted the advocate’s income and made their activist role less relevant. So they encouraged people to vote against the recreational bill.

I do not know how much of an influence the advocate had on the vote results. But medical marijuana activists had a lot of sway on the general medical marijuana community, many of whom were first time consumers being prescribed cannabis for pain.

https://ballotpedia.org/Oregon_Regulated_Medical_Marijuana_Supply_System_Act,Measure_74(2010)

Election results. 1 out of 5 people voted. Republicans won almost across the board. A lack of votes leads to republican victories. Cops were complaining about not being able to write tickets anymore (literally), and no one bothered to vote.