Window bars vs alarms in urban rowhouse?

[Johann Jells]

One of my tenants is freaking out because someone was creeping around on the fire escape and tried to open her kitchen window. She had the preventer tabs set so it didn't open, and her window alarm went off. The intruder scampered. So now she wants bars on these 3rd floor windows. 

I hate them, looks like a prison. They used to be ubiquitous around here pre-gentrification, but they are not so common anymore. It's especially problematic with the kitchen because it has to open and the fire escape prevents having one outside that swing out. I really don't want one inside, they're hideous and I've put a lot of effort into a nice renovation.

Am I wrong in thinking that the alarm and window locks did their job and she should calm down or leave? Or are bars still a common solution to this kind of security issue? Are there different types of alarms I should know about? I feel having my own cameras is pointless. What, am I supposed to monitor them 24/7? Thieves around here don't care about being recorded, they snatch packages off doorsteps right in front of Ring Cams.