It doesn’t happen now, players with talent are immediately absorbed into an AFL club with the blessing of their parent club.
In the old days however certainly Sydney, and I imagine country clubs, were very reluctant to let their players go.
Such was the situation with Freddie Davies. A product of Double Bay School and later the Eastern Suburbs Club, Fred was bathed in talent. He represented NSW Schoolboys in 1921 and again in Brisbane in 1922 as captain. He later captained the NSW state team at the age of 23 against the VFL at the SCG.
Prior to this Fred represented the state in the 1927 National All-States Carnival and was beseiged by VFL clubs for his signature.
In those days local clubs and state bodies frowned on such action and went to great lengths to discredit the Melbourne clubs.
In early 1928 when North Melbourne attempted to secure his clearance they were exposed when it was reported that:
“It was a big offer (£4/10/ a week to play football) and a job in the bargain for Davies to turn down. He did not know what the other players had been offered. Mr. Thomas, (said Mr. Smith) explained the whole position and there was not the slightest possible doubt that negotiations with the three players had reached an advanced stage when Mr. Thomas called on me. THE THREE PLAYERS. Fred Davies was the best all-round player in the League last season. Twenty years of age, he weighs 11st. and is 5ft 11 in. With his exceptional capacity for ‘mixing it’ in any company, Davies would he sure to succeed in Melbourne League football. He moves into position well, and, in addition to handling the ball ably, is a fine kick and marksman. He is a product of the Double Bay School. When several Victorian critics endeavoured to select an Australian team after tbe recent Carnival games in Melbourne, Davies was the only New South Wales player to receive popular recognition.” [1}
Then, on the same day, the Sydney Sun reported on a letter sent to North Melbourne from the Secretary of Davies’s Eastern Suburbs club:
CLEARANCE REFUSED FOR VICTORIAN CLUB MELBOURNE, Wednesday.
The Eastern Suburbs Australian Rules Football Club, Sydney, has refused a clearance to the North Melbourne Club of F. Davies. Alrc McWhinney, secretary of the club, explains the position in the following letter to Stan Thomas, secretary of the North Melbourne Club: — “Your committee and yourself cannot realise the strenuous fight that we in Sydney have had in the past to foster the good old Australian game. If, when we are making steady progress, we have to lose players of the type of F. Davles (by trafficking), then we in Sydney will have to close up business and go back to Rugby. “It is only on very rare occasions that we get a local, player like Davles; who is not only a draw for our club, but a big draw for our game In general and while we can produce his class of player the game is going to make rapid strides in Sydney. Therefore my committee appeals to your club to refrain from encouraging players from Sydney when you have so many to choose from In Victoria.” 
Now today there would be hell to pay if a club took this action but it kept ‘Snowy’ Davies in Sydney until 1930 when he took the field for Fitzroy. During that time Easts were runners up in 1928 but failed to make the four in 1929.
Fitzroy were a strong club in those days while North, who hadonly been admitted to the League in 1924, struggled.
Davies went on to play from 1930-34 for Fitzroy and captained the side in his final year. Upon his return to Sydney he played for St George, firstly under Ted Shields, then Bub Phelan and finally under former Footscray player, Jack Hayes. He was appointed captain and coach of the club in 1938 when they won their second consecutive premiership. Fred was 32.
The only other player we know of who had problems gaining a clearance was Mark McClure when he was recruited by Carlton from East Sydney (same club). Easts officials delayed the clearance in the hope of a securing substantial ‘transfer fee’ only to have the Carlton Secretary tell them ” …. if you don’t clear him we will sign someone else and he can stay in Sydney.” (or words to that effect)  The clearance was quickly despatched to Melbourne after the matter went before a special meeting of the NSWAFL administration on June 21, just before the clearance cutoff date.  McClure went on to play 243 games over eleven seasons with Carlton and was captain of the club in 1986.
 Referee Wednesday 15 February 1928 p 13 Article
 Sun Wednesday 15 February 1928, page 7
 Anecdotal – club official
 Sydney Sun 23 June 1973