While we cannot stop anyone doing this (Fang could have done this without stating) it is rather bad taste in an event which is mainly for fun, enjoyment and benefit to both parties. The organisers spend their good time planning and organising, including myself making all the items, to give mutual benefit to the slaves and masters who gain coin and a helper respectively. If the slave was not to fulfil their bargain it seems unfair, or even a con as the master has paid coin for the leash and the slave is not fulfilling their end of the bargain.
Consider this Fang, since I dont think you intend to con people but the slave is the one that gains the most from this situation and to refuse to participate (or even worse, just not play MD for that period) is really poor taste.
Seems something the MC could deal with. This seems a sensible suggestion.