I know some professional contest joiners...

Every day submit hundreds of contest... small prize like cap to RM50 cash voucher to oversea holidays 7 nights HK, Taiwan, Japan, etc including flight and accomodations, etc...

big company one got Commissioner of Oaths or some sort like external auditors if doing lucky draw one.
small company maybe can cheat and put boss own relative, close fren, etc

those write slogan one harder to scam, unless few internal party pakat to scam as same case need commiioner of oaths and 3rd party like external auditors present to verify