Don't believe everything that you see on social media. That will be the best option in order for you to avoid scams. Try to check their main website if this is really legit. usually, if the project really is legit they posted the contest in the ann thread on the forum and in their own website. if not, I think this is certainly a scam.
indeed, I assume that giving away Ethereum or certain amount of coins isn't that always free and real because most of the time crypto projects will be conducting bounty campaigns in order to effectively promote their Crypto projects than just giving away tokens and coins through social media. that's doesn't right.
Airdrops aren't that good to participate as well because most of them are scams and bogus.