When Boaz was sleeping at the threshing floor instead of at home was Ruth's behavior immoral?

Ruth 3:7 And after Boaz had eaten and drunk, and his heart was cheerful, he went to lie down at the end of the heap of grain; and she came softly, uncovered his feet, and lay down.

This may seem very irregular to us in our culture, but actually it was the accepted practice in that day and there was nothing evil or suggestive about it.