The Green Initiative Coalition has put forth a proposal to ban plastic bags in grocery stores, arguing that such a ban will significantly reduce the amount of plastic waste in the environment. They cite numerous studies showing that countries that have implemented similar bans experienced a marked decline in pollution levels. However, some local business owners contend that this change will only lead customers to purchase thicker plastic bags or alternative items that might still contribute to overall waste.

In evaluating the feasibility of the Coalition's proposal, what assumption must be true for their argument to hold?