Halliday & Matthiessen (2014: 544-5):
But even with some cognitive and verbal processes, a projected element may occur which is not projected by that process; for example:
[cognitive]
Just before dress rehearsal, under pressure from the company, he reluctantly accepted [[that such ideas were outmoded]], and dropped them.
The second category of temple land was particularly important and it was accepted [[that the holders of this land could sub-lease it]].
[verbal]
‘That was pretty obvious,’ smiled Sir Cedric, ‘and I admit [[I once had doubts about you]]’.
With sly winks and discreet sniggering he conveyed [[[that he knew very well || that there was a great deal more than Philip confessed]]].
And there will always be ‘borderline cases’, instances where the line is hard to draw.