Jesus, Himself, rebuked people for pursuing Him because of miracles, referring to them as things that do not endure. The false prophet BarJesus sought to turn Sergius Paulus away from the faith. So also do false prophets withstand the truth and seek to cast stumblingblocks before those presenting the word and those who would receive it. Therefore, false prophets sprinkle a little truth here and there in the midst of the garbage they preach. The doctrines taught and methods embraced by false prophets result in resistance to the truth.
False prophets are covetous of followers.
Hence, false prophets are very likely to boast in the number of people that attend their churches. Please note that this statement is not meant to condemn everyone that mentions the number of people attending a service or church. Boasting in numbers and simply mentioning numbers are two different things. Boasting is related to pride. The number of people attending a church is deceitful if the ratio between attendees and sheep is extremely different.