I agree with Jane. It's a marketing ploy to sell stuff that people didn't know they (don't) need. Dogs and cats 'must' be treated for fleas every month, so why not apply something to your rabbit as well?
Awareness of flystrike is, however, very important. I've lost one rabbit to it. It was horrific, despite catching it in time. I lost the rabbit a few days later due to the shock. I've had a couple more who had to be protected in their exceptional circumstances - they were outdoor rabbits with open wounds on the face from jaw abscess surgery. They had F10 with insecticide applied as needed. I won't use Rearguard ever again - awful to use, expensive, has common side effects which affect rabbit appetite, and is only licenced to be used on the bum where there is no broken skin - it can't be used on any other area, so has its limitations. It may also give a false sense of security if used regularly for no particular reason. I would not advocate the regular use of flystrike prevention treatments on a normal, healthy rabbit.
Education for the care of rabbits is slowly improving - but there is still a long way to go. Space, company, neuter, vaccinate and hay. They don't need fancy (tiny) hutches and lots of manufactured 'treats'.
