Re: Anti-beartrap - provided you use a safe method of loading a rifle, particularyly those with a sliding breech (HW77 etc) i.e. keeping hold of the lever while inserting the pellet, then such a device is not needed.
However human nature being what it is, invariably you will find people who handles these kind of guns in a more casual manner who would then get upset if the unfortunate event of having a piece of their thumb or finger removed happens.
With the current culture of litigation in both UK and US, whereby people feel the need to sue someone else for acts that are largely attributable to their own stupidity, the manufacturers take all reasonable steps to ensure that they don't get sued.
The anti-bearttrap on the HW77/97 lies on the underside of the action and blocks the trigger sear from moving while the lever is not locked into the firng position. It is a pretty reliable system but does prevent you from de-cocking the rifle.
The Air Arms TX200 and HC from the Mk2 onwards feature a side mounted ratchet that requires to be manually disengaged to return the underlever to the shooting position. The beauty of this system is it allows the rifle to be decocked. It is potentially a little noisy in operation, but it can ba manually over-ridden during the cocking stroke but left safely engaged for loading.
The RWS/Diana Mod 52 and derivatives feature a simple manual ratchet to prevent an accident.
IIRC the Gamo rifles are fitted with anti-beartraps that cannot be over-ridden.
Hope that helps.