Copying bets from unknown bettors is a good practice for people who want to gamble but do not know what to choose.
Although this can give risk by selecting an unknown bettor, we can expect to make wins if they win.
Copying bets because we do not know what to choose is stupid imo, it is even better to not gamble at all than risking our money on others especially if the one we try to follow is unknown person or just because we are a fan of him/her. Copying bets is fine if we know who is the one we try to follow, lets say he is a proven and well experienced sports bettor.
If you bet by choosing to copy bets from unknown bettors to get a win and make money, that's stupid, but if it's just for fun, it's not stupid because that person is willing to risk losing his money by placing bets from bettors who unknown.
It all comes back to our goal in betting and what we want to get from betting or copying bets from other bettors.
It would be good if we had knowledge from the match and then we could check all bettors and copy their bets.
This is the best thing to do, at least we do not do 100% copy without doing anything else. We should analyze the bets ourselves as well, if we think that the bets is good enough after our own analysis then we can go for it or maybe we can change something with the bets.
By analyzing bets and placing bets from bettors with a high success rate of winning, we can be sure we will also win with them.
But often, it is difficult for us to decide to copy bets from other bettors because they have almost the same experience as the others.
They provide a good betting record throughout their career so it takes us some time to pick them up.