Other players do intentionally drop trophies so that they can get more 3 star victories. This is generally an effort to farm mutagen. They leave their base undefended when GC is not in sessions so that they will lose intentionally and then spend a few LL tries to lose intentionally. By GC start they stack their base again and start doing LL.
While I think leaving your base undefended can help in the mutagen farming, purposely losing an attack is counterproductive.
Just remember ben, the more people that attack you, whether they win or lose, the more souls you get. You want people to attack you. At a higher trophy rank you might earn 15+ souls per hour but if you're not getting attacked every hour then you're missing out. If you're sitting around 10 souls/hour rank you might get attacked every hour and end up with a thousand souls per day.