Sorry for cross posting I've asked this question in OL mailing list, but not get response yet. It is very important for me to resolve this issue. I've made a little example that reflect my problem. It's not clear for me why GM layer loads tiles even if this layer is disabled (it can be observed against firebug in Firefox) and how I can to prevent this?
OL only load tiles if the layer is "active".
I tested your sample in Chrome and works fine. Once the initial view is fully loaded if I move around only OSM tiles are loaded and when change to GM then the GM are loaded.
What it is true is at the beginning the GM tiles are also loaded. It can be due because you add first the GM layer to the map instead OSM. If you do so then GM is selected as base layer until you manually select OSM as base layer and meanwhile the GM tile can be loaded.