No it isn't. I've never once heard Spurs through and through legends like Mabbutt, Lineker, Hoddle or King offering their sage advice to players to join the club. In fact, I've never heard Le Tissier do it for Southampton, nor Shearer for Newcastle, nor Southall for Everton. To their credit, you also don't see the likes of Adams, Henry and Bergkamp being wheeled out every transfer window to recruit for Arsenal.
No, there are essentially 3 teams in the entire country whose ex players consider themselves morally incorruptible to the questionable practice of publicly tapping up employees of other clubs: Liverpool, Chelsea and United.
And don't say 'that's because of the success of the clubs', because you and United have been signing **** for years now.