In BW or HGSS? In BW, I know ID/SID abuse is not necessary for capturing wild shiny's, but the shiny frames are relatively higher. In HGSS, Idk if you need to, but I think you do.
Your ID/SID determines the shininess of a pokemon in G4. So when you abuse your ID/SID, you're abusing to get an ID/SID combo that yields a shiny spread for a certain nature and IVs. I abused my ID/SID for an Adamant spread and got a BUNCH of other shiny spreads, but the IVs are all terrible bar my Adamant one.