There are two types of document checks. One is to ensure you have the right document eg a valid passport. You can check in at a machine and once the passport is electronically read and you get your boarding pass, you do not need to see a GA or check in agent and will not be paged to the desk.
The document check while boarding is for all international flights and the purpose here seems to be cursory check - that you have a passport and it matches the name on the ticket. Does not seem to be a in depth check.
You cannot completely avoid a document check cross border.