<p>Completely unreasonable, and you need to tell her as much. Now that it has happened more than once, she’s going to think it’s OK to work this way.</p>
<p>You need to talk this through now, and explain that you need more notice, and set time limits. It is your room, and you cannot be exiled without warning. What happens if you need something from the room, and you didn’t know ahead of time?</p>
<p>If you have your talk, and she does it again, the appropriate response is to walk in on them, and apologize for not reading her text. “Sorry, I let my battery die - I didn’t realize you were here… oops. Maybe if you had given me a heads up this morning, I would have known you might be here.”</p>
<p>If they want an hour alone to be intimate, that’s one thing. Anything more than an hour, they need to get a room elsewhere, or arrange ahead of time. Sorry if that isn’t spontaneous, but you can’t be spontaneous that way in a triple.</p>