The guitar's current or previous owner may have intentionally locked down the vibrato assembly because he/she doesn't use it and wanted improved tuning stability. The better way is to wedge a block of wood inside the body cavity as a backstop for the bridge (this improves sustain as well). PS, it's vibrato, not tremolo; but Fender and most other amplifiers have tremolo, not vibrato!
The guitar's current or previous owner may have intentionally locked down the vibrato assembly because he/she doesn't use it and wanted improved tuning stability. The better way is to wedge a block of wood inside the body cavity as a backstop for the bridge (this improves sustain as well). PS, it's vibrato, not tremolo; but Fender and most other amplifiers have tremolo, not vibrato!