The problem is what exactly counts as a poison?
The one that's caused the most bother is ALCOHOL; it is a poison, but does it count for these effects? Does immunity to poison mean you can't get drunk, does detect poison only show the presence of alcohol if you have poison in the glass?
Logically it probably should count, it can, after all, be fatal; however it clearly isn't usually used as such. Almost anything can be a poison to the system in the right dosage(vitamins etc). So do these effects somehow judge intent; are they effectively fairly useless.
What opinions - or even better, rules- apply here?