So So true, Mtnlites. BG's mannerisms are pretty unique, when taken as a whole.
1) the way he shifts his weight
2) hunches his shoulders
3) leans his body forward with head bowed
Smartly, you have all sleuthed my avatar and know that I am a dancer and a musician.
So, Mtnlites,
I will also add to your very perceptive list:
4) BG pronates his right foot ( Some of you have already said pidgeon-toed, and, yes, but it is only his right foot which twists)
5) he throws his right hip forward, kicking his right leg out, when he steps. (only on the right again)
Dancers see things in how people move to a fine degree,..... only because we have to copy NUANCES exactly, in order to get our paycheck!!!!!
BG's voice is also distinctive.
6) his timbre is affected by heavy smoking perhaps, so it is a .. "reedy", raspy, "tinny"-sounding voice.
Many sleuthers have already brought this up.
Not just the musicians. (LOL)
It is concerning that BG has not been apprehended yet. So many on this forum have noted that there are obvious mannerisms which BG exhibits that even a co-worker would see, and be compelled to call the tip-line.
(MOO: Amateur physiological speculation and too many years listening to good 70's rock.) ETA: better description