Then you still shouldn't be cheating and making the character faster. By altering tails.plr, srb2win.exe doesn't detect you did anything, so for instance, lots of people used that trick to beat the special stages by adding extra rings to srb2.srb. Altering tails.plr to go faster is cheating, and would allow you to get the secrets easier. By forcing you to make your own file, you're giving srb2win.exe the information that you added a file and hence are cheating, and it won't let you unlock anything. You can still have your fun, but you don't cause incompatibility in netgames and the game knows what you're doing, and won't screw up on things that it would otherwise have trouble with.