This mostly depends on the customs of the people who are getting married. Often, women in a traditional get treated like property, which can lead to them getting beaten up or much much worse. Women often become just machines for making babies, which can lead to numerous complications. The list of problems can go on and on.
A sea of tents is not a real thing. It is saying there are a lot of tents, like how there is a whole lot of water in the sea. Same thing for forest of electric poles.
