There is no such thing as Free lunch. Somebody is paying.
But It is no use. Dumb people will always Chase the Free/easy money promises and lose.
Few people check out How the promise work.
Take steemit: some places i see say It is Free easy money.
Its not Free: you spend time resource to earn money
Its not easy: even If you go after bots for big votes, It takes some effort to do It.
Also, If the post os less than 7 days you can take your vote back.
You are right. We need to all be careful. Nothing is free but takes work.