No offence, and not a personal comment, but imo Americans seem more confused about the difference between Sikhs, Hindus and Muslims. Maybe its a cultural thing, as all three groups are more fundamental to our culture and history than yours.
I know the difference between Sikhs (heartily welcomed) and Muslims.
Indians and Muslims, pretty easy to differentiate, esp. the women.
The Muslims at the Holiday Inn in DC were easy to spot, the white skull caps, etc.
Here in Raleigh, NC area we have a large population of Sikhs and E. Indians.
Quite a few Muslims also. Lots of Pakis.