Hooray! At last we have the answer to the $64m question.
The FRA has a definitive on the FAQ's section of the website.
Read on......
Q: Is a buff a hat?
Unless otherwise specified for a given race, the FRA considers that a buff is a hat for the purposes of mandatory kit for FRA races. However, any Race Organiser (RO) may decide not to allow buffs in this capacity, just as ROs may require additional mandatory kit to be carried such as an extra long-sleeved warm layer or survival bag.
If in any doubt, competitors wishing to carry a buff are advised to ensure they take a separate hat with them to the race and to check at Registration. ROs who do not intend to accept buffs as hats are encouraged to publicise this in advance (being in the minority).
As with other requirements, the rules cannot cater for every possibility and a degree of reasonableness on both sides is assumed. A 40g buff double-folded is likely to be at least as effective as a 20g hat, and should therefore be accepted unless stated otherwise. However, wafer-thin plastic gloves picked up at a petrol station would clearly not meet the stipulation for gloves in a fell race. Similarly, one jelly baby would not suffice as “food” for a pre-race kit check, nor would a dog whistle, a small child's waterproof trousers or a map of the wrong race be acceptable.
In summary: the decision is the RO's. The FRA would support any RO choosing to exclude or disqualify a competitor, including (or especially) those obviously seeking to circumvent the rules, provided that any non-standard requirements had been publicised clearly in advance.
