To have your path obstructed by a group of geriatrics. Typically happening while shopping or while using public transit, a single senior or a group of pre-corpses can cause issues for movement. There is typically nothing that can be done to remove them. It is recommended to wait in an adjacent area or store until the path is clear. You could excuse yourself, but their feeble eyes and ears are ill-equipped to notice anyone nearby half the time making the effort moot. This can also be used to describe the wasted time used by some old fart while at a cashier or fumbling to get a needed pass or ticket.
Person 1: Hey, what took you so long to get groceries?
Person 2: Seniors day today, whole store was a massive geri-block. Took forever just to get to the back for milk. You do it next time.