Originally Posted by
Schweden
While driving into forbidden countries would most likely invalidate Sixt's included third-party insurance, I'm wondering if my personal car insurance's rental car liability insurance could replace it? If so, the only risk I would have is driving without LDW, although this could possibly be covered by my credit card.
It would appear that you're based in Canada. If Canadian auto insurance is similar to what's offered in the US, your liability coverage is valid only to Canada and the US.
As others have written, your credit card LDW will not cover you if you are in breach of the rental contract.