Russians are really bad about impersonation. Both sides keep changing their arm bands for ID because of that. That's why they're using replaceable ducktape. They're temporary. If you stick with one color, the enemy impersonates you. It's a colour code. I know that's morally wrong, but that's what's happening. There's also NO chance that helps with identifying your limb /s. I'm not a combatant, but I've been following Ukrainen info lines for a while. They talked about it once. I'll edit if I can find a source.
Edit: I can't find the example of a soldier talking about the arm bands, but here's some evidence (I saw it, but it was removed):
"During the Russian invasion of Ukraine, Ukrainian ground forces started to use reflective yellow armbands, similar to yellow reflective belts used in the U.S. Army.[2] Later, they switched the armband color to blue (the other color of the Ukrainian flag) to prevent Russians from infiltrating their ranks.[3]" Wikipedia
"Russian forces have used red, as well as gray, white cloth, neon green, silver reflective bands, and black and orange ribbon. The black and orange ribbon is a reference to the Order of Saint George, the highest military decoration in the Russian Federation. The colors of the ribbon are said to symbolize war's fire and gunpowder, the death and resurrection of Saint George, or the colors of the original Russian imperial coat of arms." Wikipedia
I don't blame them for hiding the exact info. Loose lips sink ships.
Edit 2: Here's an article with the person who gave the info: