SSB out-of-band?

There is an interesting piece on Southgate News about transmitting out of band. This is particularly important on 60m where the allocations are very small. The important thing is that the dial frequency may be in band but some of the modulation may not be! 

See http://www.southgatearc.org/news/2021/january/how-far-you-can-turn-the-dial-when-transmitting-ssb.htm#.YCEkAyuTLrc