What a mess with concepts! Blocking is good but is independent to fire at 2 against unescorted transports.
wake up to reality.
In the poll i have on going the question is if subs can attack on 1 or 2 the unscorted transports that move to or through the sea zone the sub is as described in Europe rules, or if they lose this ability like Alpha does.
blocking or not has nothing to do with this.
The 2 rules you put as exclusive can be mutual, in other words you can use both.
In the poll i have going on after clarifying really well what the poll was about the result is 24 votes to maintain sneack attack and 3 votes to remove sneack attack and the results before the clarification where 14 votes to maintain and 2 to abbolish so giving the actual total of 38 votes to maintain and 5 to abbolish sneack attack against unescorted transports.
And it is possible to have sneack attack rule in simultaneous with block rule:
example: usa unescorted transport in the middle of atlantic moves through a zone with a german sub and this sub sneack attacks the transport. In the same round of play another unescorted usa transport is blocked to participate in an amphibious assault in mediterrain by the presence of an italian sub.