Hmmm. I think Ruger would just ring the bell for the heck of it.
I thought I could watch him and take him out when necessary, but I've only caught him a few times, and when I do he either runs under the bed or under the coffee table.
I don't know. I'm "guessing" that if I miss a scheduled walk he'll let me know. I do nothing when he makes a mistake, which are few now, and tons of praise and treats when he goes outside.
He goes out whenever he comes out of the crate and after meals and right before bed. If I'm home he has the whole upstairs to himself, but it's a pretty small place with a combo LR/Kitchen.