It has never been true for any modern wristguards that they simply move the break. There were two documented cases of extremely primitive rollerblading wristguards where they broke their arm further up, but no causality was ever actually established. Modern, well designed wristguards dissipate a ridiculous amount of force, the one I linked is one of the most effective, but is fairly bulky. Others are maybe not as effective, but more streamlined.
Wrist guards for snowboarders - www.ski-injury.com - Ski Injury
The argument that wrist guards
are no good, because 'they just move the energy to your arm and break that instead" is utter BS.
First of all, wrist guards absorb (at least) some of the impact energy
(in other words, the transfer to the forearm is not perfectly efficient). The amount of energy absorbed may vary depending on the type of wrist guard, the nature of the fall, etc. - but every bit helps, so that it is plus for wrist guards.
Second, the transfer of (the remaining) energy is desirable
, because the bones and joints in the rest of the arm are stronger and better able to withstand the energy from a fall.
Finally, even if there is a resulting injury to the forearm, this is still preferable over an injured/broken wrist
as it much has less potential for permanent damage and typically heals with fewer complications.