Im presuming you think he must therefore be free to challenge the acting SH? Is he free to stand alongside the first receiver?
If defenders dont ever jackal/ruck at a 1v1 tackle ( thereby never creating a offside line ) then presumably your saying defenders are permitted to intermingle with attackers , if so this won't be an attractive code for any watcher.
Well I don't like it either, but that is precisely what the Law says, or rather doesn't say. The offside lines appear when the ruck is formed. If a ruck doesn't ever form, then there are no offside lines. Simples
Perhaps a modified version of the previously failed
"offside at the tackle" could be trialled.
Rather than the tackle offside lines appearing the moment the ball carrier is grounded (which is what happened in the 2008 ELV), perhaps they could appear the moment any player gets their hands on the ball, either by taking it off the tackled player, or by picking it up after the tackled player releases it. i.e.,
1. The jackler grabs the ball = offside lines appear
2. In the event there no-one attempts to jackle (i.e. the scenario The BFG outlines in post 20) then offside lines appear when the acting SH picks up the ball.