Another interesting selection!
I have very little knowledge of how borders operate apart from the occasional news on the closing/opening of the borders for goods to come into or be taken out of the country. But I am sure that just as civil rules exist, the rationale behind the close borders is highly plausible.

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To better understand the question, I asked myself or rather I thought to myself, "what would it be like if I opened my doors to everyone and anyone and they did same to me of/and everyone else.. Ever since then, I’ve been thinking about it. Because, trust me, I don’t want everyone in my house and I’m sure they do not want everyone in their houses as well.
Because you can’t let anything and everything into your space. You get me?
Meanwhile, bear in mind that some good effects also have bad sides and vice versa.
So, based on my thoughts and findings, here it goes...
Disadvantages
•Anyway, if we have open borders , with people having the freewill to go anywhere they please, the likelihood that we would prevent infiltration by criminals or enemies of the country would be on the low.
•With open borders and no restrictions to people who can get in, some countries will be unequipped to handle the influx.
•You know, chances are that everyone would want to go to the most developed countries of the world thereby creating an overpopulation and most likely the amenities in that country would not be enough to cater for the people of the country. This will in turn reduce their economic power.
•And then the loss of belief and culture as the inflow of foreigners will cause a change in the system. This may be a positive or negative change.
•There will be and iot of movements going which would result in chaos from migration because too many people would want to concentrate on the well developed places of the world
Advantages
•It allows mobility of Labor and provides more opportunities to and for workers. Even more, a country's workforce increases.
•The opening will eliminate illegal migration and illegal employment. But this can undermine the rule of law in well established places as there is little guarantee that laws will be upheld and maintained....negative and positive sort of.
•Imagine the borders of the world gets to be open for anyone to leave wherever they want. We would probably have different people of different races and different tribes and different beliefs coming together and maybe in some way, it will foster some sort of unity.
Why are there even closed borders when by law, we(human beings) have the right and the freedom of movement. Should this right be curtailed?
But, of course, everyone cannot go everywhere because there are certain criterias for one to meet to be able to belong to a particular place.
I do not think that there are as many advantages to unrestricted movement as there are disadvantages. The laid down border rules of a country are fo ensure the safety of the people and manage-able economic value of that country.
Thanks for gracing tthis post.
Greetings!