Cant really bother the bizzys because to be honest not much they'll be able to do due to no signs of forced entry
Like the spray paint idea Groverdog
The thing is FD the bricks below the window may be a known burglars 'modus operandi' and they will certainly keep alook out if this is so.I wouldn't go out to them though,as you never know what might happen.The knife may get used on you,or,you may be forced to use it on them,and,then you will be in the dock.(not worth it)
Good idea Higgins,very pro-active,and,does put people off.