My club had insurance via BFTA some years ago, and I know very well the gaps between the floorboards, but that's not for this forum.
Bringing it back to the point at issue, if a person turns up and does not have a BFTA number and maybe can't even prove membership of a club, affiliated or not, how is that person's position in respect of being a visitor for insurance purposes
any different from someone who has just left their card in another jacket?
It would seem that so long as they have signed in then whatever little cover exists also extends to them, and the hosting club is not in violation of its own cover.
I'm only familiar with our domestic arrangements but I'm sure other regions have league comps where clubs in that region host a round of the league, and members from other clubs in that region take part in the day's competition. Officially then, they should all be logged in as visitors on the day. In practice, do they sign a visitors' book? At our club we keep a copy of all of the names that have paid to take part in the competition, it's a separate piece (or pieces) of paper but constitutes a record of who was on site.