First off, when you claim coroner I only ever see these three reactions:
1. You are immediately accused of being janitor (regardless if you were already accused or not, or if there is even evidence of a janitor)
2. If you were already accused, they lynch you anyway because "coroner is useless and it's no big loss"
3. If you try to accuse someone with night evidence, you are called a "creative executioner" or ignored.
Second, apparently there is a myth floating around that coroner never appears in games unless there is a janitor. I've rolled coroner too many times without a janitor to even believe this, but a lot of pubs I've seen do believe it. So generally claiming coroner around these types gets me lynched for above reasons.
Coroner is a useful role in certain setups, but it is entirely underestimated and ignored by most players. Also I've rolled 8 coroners in a row now.