After having let it simmer for a while, I think the biggest reason why read unhygienic is less of a problem, is because it will raise an error at compile-time, when the context of the macro doesn’t provide the implicitly read variable (is this always the case? I might be wrong here). So the implicitness becomes explicit, when you try to compile such code 
It never gets to be compiled, luckily.
Whereas write unhygienic code can go unnoticed, which is a big problem, if you weren’t expecting that.
So this is what I get to:
hygienic > read hygienic (won’t compile if expectation about variable is not met) > write hygienic (can go unnoticed)
My understanding of macro hygiene is becoming more solid from this thought exercise, so thanks!
