I've no problem with Starbucks essentially requesting but not banning open carry, they're a business which seems to be supportive of gun rights, thus the appreciation day. Harming their business is no way to thank them.
...asking open carriers to leave their guns home is no way of thanking their customers. But I agree the shotgun makes no sense in everyday life.
(On a personal note, I don't like "open carry" as a tactical matter. I want them to be surprised when they try to mug me.)
On a personal note, I don't either. Unless you've a reason to carry a long arm, imo it defeats the purpose.