they hadn't really considered just how many referees are needed at these type of events.
A common fault of first time organisers, and also those who should know better after many years, is to underetimate how many referees they need on the day, and to have reserves as someone always drops out at the last moment.
Rule of thumb is that a reasonably fit referee will do 5/6 matches of average standard sevens. The fit "15 on bleep test" refs can manage 8 or more matches.
Some also forget, or leave it very late, to ask the Society for referees and don't realise just how many other tournies / festivals / matches are happening on the same day.
Finally the better organisers often lay on
a) reserved referees' car parking close to clubhouse
b) pre-written match cards
c) dedicated referee changing / showering / tent with shade
d) physio on call at the ground
e) chilled water, water, water & water (especially if 'scorchio')
f) nosebag
g) post tourny momento - medal, six pack of local brew (HSB or Badgers), commerative tankard, etc
h) special officials stash
i) either a referee manager, or
in advance ask Society for one
j) match balls - I have had to beg borrow steal and use my own out of my car boot before now
k) pitch marshalls to get teams there, hold onto match balls, etc
These well organised events tend to be top of the list for refs requests the next season.