De Google FAQ :
With some exceptions, punctuation is ignored (that is, you can't search for @#$%^&*()=+[]\ and other special characters).
Seguindo aqui :
Punctuation that is not ignored
- Punctuation in popular terms that have particular meanings, like [ C++] or [ C# ] (both are names of programming languages), are not ignored.
- The dollar sign ($) is used to indicate prices. [ nikon 400 ] and [ nikon $400 ] will give different results.
- The hyphen - is sometimes used as a signal that the two words around it are very strongly connected. (Unless there is no space after the - and a space before it, in which case it is a negative sign.)
- The underscore symbol _ is not ignored when it connects two words, e.g. [ quick_sort ].
Então, parece que ? será ignorado pelo Google, independentemente de como você o insere no mecanismo de pesquisa.
Os únicos mecanismos de pesquisa que eu vi conhecendo a pontuação foram os mecanismos de pesquisa código .