Looks like I'll just have to eat the bandwidth charges
And therein lies the conundrum, not only does this mean that Google are condoning hotlinking and you have to pay the bandwidth for these thieves, in my case it would seriously affect my AdSense CTR and eCPM massively.
It really does depend how many images you have that are hotlinked and regularly used on those sites. If it were just my widget trade using them to display decent brochure images I wouldn't mind but when thousands of social networkers, myspacers, etc decide to use my images for backgrounds, and some of them are getting hundreds and thousands of views per day, well, the bandwidth just goes bananas.
Since my peak bandwidth month in May this year so far this month I have used just over 19% of that bandwidth therefore it looks like it will end up at about 30%!
That's one heck of a saving however bear in mind my bandwidth usage before I clamped down on it was increasing by ~15% per month...as we say in the UK, do the maths:-)
At 5 months bandwidth has doubled.
Another 3 months and bandwidth has doubled again
Another 2 months and bandwidth has doubled again.
In less than a year one's bandwidth has increased 400%!