Which of the following is considered an illegal activity for dealers?

Submitting title after the allowed timeframe is considered an illegal activity for dealers because it violates the regulations governing the transfer of vehicle ownership. In Wisconsin, like many other states, there are specific timeframes within which dealers must execute title transfers to ensure that ownership changes are properly documented and that all legal aspects of vehicle sales are appropriately managed. Failure to follow these timelines can lead to penalties, fines, or disciplinary action against the dealer's license, as it can impede the process of tracking vehicle ownership and could enable fraud or title washing.

In contrast, selling used vehicles only, accepting trades from customers, and performing written agreements are all standard practices within the automotive sales industry. These activities are compliant with state regulations, as they are integral aspects of day-to-day operations in a dealership. Therefore, the focus of legal compliance should be on adhering to required processes such as timely title submissions to avoid legal repercussions.