Put a bike on a trailer or in a van and, unless you've got it really well sorted or are extremely lucky, it'll try to roll backwards and forwards. Even when it's in gear there's a little bit of movement. And that movement allows whatever you're tying it down with to either chafe against the body, frame, bars, whatever or to gradually tighten and slacken, which will work it loose. Or, if you're really unlucky, both.
Now the canny bike transporter straps a bit of bungee cord around the brake lever to lock it. Which is OK in a slightly hit and miss, bings off into the undergrowth when you least expect it sort of way. In other words, not really OK at all.
Acebikes have come up with the BrakeFix - a very neat plastic clip which hooks around the right handlebar and front brake lever. Squeeze the brake on, press the clip down and your front brake is locked on. The bike isn't going anywhere.
Use it in the van, on the trailer, parking the bike on a slope, whenever you like. It's not expensive at just over a fiver, it's stupidly easy to use, it's ever so nicely made and it's nice and small so it's easy to carry.
Interestingly, Acebikes carry the slogan "Innovative Equipment" on their products and packaging. That would normally be enough to get a jaded hack like me mounting my high horse and charging off on a righteously indignant crusade about people claiming to be innovative when they are, in fact, nothing of the sort. Not this time though - these guys are genuinely coming up with products that have been thought through as solutions to real problems. Or at least ways to make our lives easier, which is close to the same thing.
Brakefix is a great idea that, like so many great ideas, is so simple you just slap your forehead and ask why you didn't think of it yourself. I've got one in my bag all the time, and would thoroughly recommend you do the same - it's astounding just how often I use it...
You can find Acebikes, and a list of local dealers, at http://www.acebikes.com
There is also a video explaining a bit more about BrakeFix here.