Why not compete as USFA member? It is not restricted by clubs.
1. http://www.usfencing.org/rjccresources
Club competitions are open only to club members. But USFA has non-club competitions.
2. club events clarification: e.g. dcfencing.com/
"What are the different kinds of competitions?
Now that you’ve learned the basics of fencing, it’s time to start competing. DCFC runs competitions for our youngest fencers on a regular basis; they are not open to fencers outside the club and do not award ratings. For these in-club competitions it is not necessary to be a member of the United States Fencing Association (USFA). Outside the club, competitions can be restricted by age, gender, or rating. To compete in these competitions, one must join the USFA, which can be done online here."