High rise window safety - restrictors/locks?

I've just moved into a high rise where the gusty winds can cause the windows to blow open far too wide. We have no kids but I'm nevertheless concerned that one of us could literally fall out of the window leaning out to grab the latch to pull it shut! (I realise that sounds ridiculous but bear with me.) I've seen on the forums that people have had locksmiths and handy-men come round to install wires or locks on windows to child-proof them...I'm hoping to avoid installing something permanent as the landlord is already starting to get peed off with our defect notifications and I have a feeling she's going to go nuts if I ask for permission to drill holes in the window frames, even at my own expense. Has anyone got any suggestions for devices I can buy to put on the windows to restrict how far they open? Or am I going to have to bite the bullet and call the landlord?