I had wanted it for compatibility with existing patches that expected the leading slash.
More detail: it is actually for the PdWrapper.pd that simulates the MobMuPlat app layer when developing on a laptop. The PdWrapper had previously used mrpeach OSC objects which, IIRC, kept the slashes. The editor sends an OSC message on GUI widget interaction, to be routed to the Pd patch being developed by the user. MobMuPlat (on device) reports the OSC message from the widget with the slash, so the PdWrapper.pd should do the same.
Is there a rationale for removing the slashes?