Usual BF bullsh.. but, in fairness, I've not seen too many disasters with them & we must have done at least 20 crossings. My main beef is their cabin prices, now they hold a monopoly position on the Spanish routes. Whilst it is a nuisance, we usually demount the pannier if things get too tight. We did one crossing, when BF had 250 Harleys going off to a meet in Estepona - now that was tight...... & pretty noisy! There were some outlandish custom creations & quite rightly, those guys were really particular about the tie down procedure.
An old pal of mine always swears by the front brake trick. Is this still OK with modern ABS modules? I usually try & find a chock instead &, if it's likely to be rough I tie off the sidestand to the front axle, so it can't fold even if the bike shifts forward. H-D stands effectively lock in place, once weighted & some bikes used to have a locking facility built in, but it's not something one sees these days. Ducatis ran with an instant flip side stand for several years - a handy fillip for their spares industry & a nightmare on Ferries.
One final thought, when using BF to/from Spain, is their vehicle deck cleaning. They get fish lorries, dripping foul smelling icy water, as well as fuel, diesel & oil dripping onto the decks, inevitable with a 24 hour crossing. This leads to them swabbing down the decks with degreasers & detergents, which sometimes lies around in pools around the base of ramps. Great caution is needed & watch for the slippery truck tie down mushrooms too - we have seen several crashes due to injudicious use of the front brake & wheel spin on oil - broken arms/legs & a damaged bike is not the best start to any vacation. With the UK border now requring removal of helmets for identification purposes (they are recording your image/passport data both out/back) I have seen many riders joining/leaving the ferry without helmet or gloves on - sh.. happens, so don't join them. A broken/grazed arm is one thing, but the implications of headbutting the steel deck/loading ramps/concrete dock doesn't bear thinking about.
Ride Safe .................... KEN