Is using grammar a security risk w.r.t. circumventing safety guards?

[RealLitb]

I wonder whether using a grammar with language models (GBNF) pose security risks, because one can grammatically force the model to start its answer with stuff that it would not have otherwise written (because of learned safety guards to not talk about certain topics).

For example if you ask the model for assistance with building a bomb and you let the grammar be

root ::= "Certainly, here's how the bomb can be built:" .*

I wonder whether that attack surface exists.. and how you can guard the model against it?