If you go in the home end as an away fan and don’t keep quiet you deserve a shellacking. I’ve done several home ends and always kept shtum. It’s an unwritten rule that most fans accept and understand.
You often get sussed out even if you keep quiet as you don't cheers at the right time or join in with their songs or celebrations if they score. Happened to me at Blackburn in our 4-1 promotion game. I was told if I kept my head down I'd be okay and I did. The funny thing is the lad to my left was a Blue as well so I had a kindred spirit there at least.