Actually, the WPA rules do not clearly forbid the use of the bridge as Oscar and Kyren used it. The wording is not perfectly clear. Trust me on that one.
The wording is more clear in the BCAPL rules.
Whether the Oscar/Kyren use should be permitted at pool is another matter. It seems to be OK in snooker.
It is very rare for a pool table to have a good set of bridges available if you compare them to what is available on the typical snooker match table. One argument for allowing creative use of the bridge stick is to make up for the failure of the room/promoter/equipment supplier to provide an adequate set of bridges.
As for the suggestion that only one bridge should be allowed, until pool tables get spiders and swan's necks I think that's a really bad idea. Those who haven't seen the Russo Interlocking Bridge Head should check it out.
If the goal is to outlaw "innovative" uses, then I think the rules have to be even more explicit than the BCAPL rules. For example they could say, in part: "The mechanical bridge may only touch the player's bridge hand, a second bridge if one is used, the player's supported cue stick and the table and may not touch any other part of the player's body or any other object. At the instant of tip-to-ball contact the player must not touch the half of the bridge nearest the bridge head and the bridge head must be touching the table."
I suppose bridge heads need to have an equipment approval process. Maybe bridge handles as well.
Bob Jewett
Chief Editor, WPA World Standardized Rules