I have a very good friend who is a Lutheran and recently attended the Catholic wedding of a friend of hers. We were discussing it afterwards and she told me she was disturbed during the service because the priest told the congregants that non-Catholics could not only not accept Communion (which is standard), but they were not allowed to participate in the prayers either.
I am in a "mixed" marriage, Nathan is Methodist and we did not discourage everyone from not praying at our wedding, in fact, we had Nathan's minister there and he gave the final prayer and blessing.
As my friend pointed out, the Catholic and Lutheran services are very similar and she knew all the prayers already, and I can't imagine that the Church would discourage people (any people) from praying.
If someone knows more about this than me and can enlighten me I would appreciate it.