Wasn't quite sure where to put this, but I was needing some more expert PT advice.

I currently live in a ground (first)-floor condo with my boyfriend, my Aussie, and our two cats. Many neighbors here have dogs and walk them in the grassy areas. We do not have designated "yards" so the neighbors who live on the upper levels with dogs usually walk them around on the grassy areas on the ground level (they don't have the luxury that we do of just opening the back door and letting the dog out to potty).

Our cats L-O-V-E to sit on the windowsill and stare outside. However, there has been a repeated occurrence where one of the neighbors (unsure of who) will walk their dogs alongside the building our office window faces and the dogs will sit at the window and bark relentlessly at the cats. Espeon is not phased by it at all, however, this TERRIFIES Voltron and he runs and hides. I understand if the neighbor was just passing by the window, the dogs barked a few times, but they went on their way. But, no. At least half of the time, the neighbor will SIT there while the dogs are climbing up on the outside ledge, getting their nose inches from Espeon's face, and barks at her. And this will sometimes go on for 5-10 minutes while the neighbor just stands there with her two dogs!!!!!

The windows are usually closed while this is going on, but sometimes the windows are open about 6" (especially with this cooler weather we've been having) and they are L-O-U-D!!!!!!!!! I mean, who just lets their dogs sit there and bark into someone's open window?!?!?!?!?!?!

I'm worried that it's happening and stressing the cats out while I'm at work and can't be there to "save" them.

Is it unreasonable of me to put a sign in the window that says something along the lines of "PLEASE do not allow your dogs to bark at and harass our cats. Thank you! " or should I take a different approach?

Thank you