[bluntfang]

I don't think anyways arguing that oil isn't a replacement for butter. I think we're curious about the expectation. Can we expect most Indian restaurants or caterers to use oils instead of ghee? Do you need to ask them if they use ghee?

[GeneralMaximus]

Fancy Indian restaurants in the West as well as back here are almost certainly using ghee. Cheaper places might use vanaspati (a ghee substitute made with palm oil) or oil. In general, though, you can never tell for sure unless you're doing the cooking yourself.