If a customer delivers an item to a depositary bank for collection, all of the following apply:
Wis. Stat. § 404.205
The general rule is that accepting a check when the payee's endorsement is missing is not in accordance with the reasonable commercial standards of banking and the acceptance by a depositary bank of such a check for deposit is commercially unreasonable as a matter of law. This section excepts from the general rule depositary banks that receive unendorsed checks from customers when the missing endorsement is that of the customer. Schmitz v. Firstar Bank Milwaukee, 2003 WI 83, 262 Wis. 2d 672, 664 N.W.2d 594, 01-2139.