When a player gets disconnected, the game should make every effort to preserve the player's status, so that they can reconnect without loosing everything. This should not only include how much res they have, but should also include what they were (e.g. onos, HA, etc), and also where they were on the map. Of course, you would have to reconnect in a reasonable amount of time (30 sec?) and rejoin the same team in order for this to take effect.
So, if a player has not been recently attacked (within 5 sec?), and there are no enemies nearby (within 10 meters?), then a player can disconnect and reconnect, and be spawned back into the same place they were when they disconnected, as the same class that they were.
Otherwise, only the player res and kills stats would be preserved. Their class and location would be lost, as if they had died -- and they would respawn as normal.
Obviously, this doesn't cover all scenarios where a person gets accidentally disconnect. However, it is a good balance between the player who gets accidentally disconnected and someone who would exploit the feature to their advantage. This is especially important in clan/tournament matches where the results affect overall standings.
P.S. There should also be a limit to the number of times this can happen to a player during a round. Someone that is constantly being disconnected is probably better off going to a different server. However, when it happens only once or twice, they deserve another chance.