The vehicle example doesn't make sense (start engine? At most, a notification from a rented vehicle to the server that the engine has been started, which is simply not going to arrive from a bicycle).

The shopping cart example is dangerous because it looks reasonable. Actually, the removal methods define atomic operations, so they are a big deal from an architectural point of view: can the cart change while we are testing elements for removal? Can the predicates look at other elements of the cart? Self-contained special case operations might be a more correct choice after all.