Border opening can either be harmful or be helpful to a country, it works vice versa. It can be harmful in the sense that bad goods and services can be brought in,weapons can be smuggled in, illegal migration of non citizens can have quick access to a country when the border officials are corrupt.
It can also be helpful due to the price of goods and services because there will be competition in the market place there by making goods cheaper, it also strengthen international relationship.
In this case I would like to use my country as an example in Nigerian the last past four years was a tangle after the government shut down the boarder that duration difficulty was in the country cause the velocity of things was high in price and also there was a lot of economic situation all over the country and also food starvation will shower over the country and if it doesn't have a substantial boosting of local food production I will say that the country will be forced to go into starvation of food and will not be reasonable I think that should be it disadvantages right now