I think you'll find you have no control over it and subscribers get everything you publish. Do you get everything you publish in your email? If you do, so do they. I discovered this after trying to selectively send out monthly summaries because I felt daily was too much. It turned out they'd received the daily ones despite me unticking the box. The system doesn't work. They'll get it. And you can only send it once. Occasionally it doesn't go - in that instance, you can trigger it to go later. But that has nothing to do with whether the box is ticked. That's my experience anyway.

People who subscribe choose to get inundated, so don't worry about it.