I have heard groups every 3 kc or so all the way to 3.755 kc. Now I don't know about the rest of you, but I would bet we could really start a war if some of us moved down there.
The day all the slopbuckets agree to stay off the AM Window frequencies, I'll agree not to operate down there, even when those frequencies are unoccupied.
In the dead of winter, under good band condx, after about 0400 GMT, I often hear vacant spots 6 kHz wide or more, between 3750 and 3790.