With ordinary folks, no. But these people would be making their signs as they walked up the stairs because they think it would impress people. Even in a prison setting they would. But it would not matter twenty minutes later.
I would not mind it if they made their signs on the gallows in front of a crowd of onlookers. I would not even require a hood. Nor a curtain under the gallows. Let the crowd see their pride in being gang members and their fearlessness! And then let the crowd watch the crows pick out the eyes of their hanging corpses. Take 'em down after about 24 hours. Let the crowd see that. Some valuable lessons might sink in.
I favor the short drop/slow strangulation form of hanging. Just enough drop to tighten that noose real good but not enough to break the neck.
Watch’em dance out their last moments of life.
Face turns purple, eyes bug out, tongue sticks out, body jerks and spasms as it fights for breath.
Anyone convicted of multiple murders gets special treatment.
A hanging for each victim.
The short drop and rope tightening, eyes bugging, body jerking but lower them and remove the rope BEFORE strangulation. Take to the infirmary to recuperate for a day or two and repeat hanging process.
Bet they won’t be flashing gang signs after that first hanging.