system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: even if the a country like France "closes its borders", what's to stop immigrants from just crossing at a deserted field?
gpt
Sometimes there is literally nothing stopping a person from doing that. Other times there are things like fences, border patrols, or video surveillance. The levels of border control depend on the country, length of the border, specific location, and the security concerns of the moment. Often a border may be monitored or tightly controlled in specific, easy to access locations, and ignored in remote, hard to access areas.