Yep, that's one of the problems that all of us have. Especially when you happen to use a lot of stuff on your bike that just so happens to be very easy to remove. Bad enough you have to worry about if someone wants to steal your bike. But if you have a bunch of other stuff on your bike that would only take a couple seconds to remove than that too becomes a problematic issue, even if you only want to leave your bike somewhere ( out of sight ) for just a couple minutes.

I carry a little cable lock in my frame bag that I use just so I can go into a convenience store and not worry about the chance that someone might quickly grab my bike in a " casual thief of opportunity" scenario. Of course if I wanted to go into a restaurant and eat then the issue changes, especially if I can't see my bike while inside the restaurant. In that situation I would almost feel compelled to remove everything that is on a quick release. I have a lot of stuff so that would be a total PITA.

Anyway, if I had to do that I'd take off my QR lights and the protective sleeve that holds my phone and then use my helmet as a bucket to hold the stuff. Still with the flimsy cable lock I use ( which is very lightweight, slim and minimal ) a person with a set of wire clips could have my bike in seconds. That's why I won't go into a restaurant and eat unless I can see my bike while I'm eating. Not to me mention that if someone steals your seat / seatpost that would be an even bigger PITA. ( thankfully my seatpost isn't on a quick release or I'd have to take that along too or use a separate cable lock just for the seat ).