Hi Cafeol - I have a 6910 and almost 3 year old son and a 7 year old daughter (hence my need for good coffee!) :D
I have the 6910 sitting at the back of the bench all the time other than when I steam my milk, when I tip it slightly backwards and use the wheels on the back of the machine to pull it forward and do my steaming - I only bring it forward about half way up the bench when I steam, but put the steam wand on about a 45 degree angle when Im steaming. Once Ive finished steaming and have cleaned the wand and finished with the machine, I move it to the back of the bench again.
That way, at all times other than when Im steaming, its out of reach of the children or at least at a great enough distance even when Im steaming that the heat from the steam has dissipated enough not to burn.