Is multiplication by juxtaposition implicit multiplication considered higher priority than regular multiplication

In the $8 \div 2(2+2)$ debate, I keep hearing about "implicit multiplication" or "multiplication by juxtaposition" having higher priority than normal multiplication.

The argument is that $2(2+2)$ means $2$ is implicitly multiplied with the parentheses result, so it binds tighter than an explicit $\times$ or $\div$.

I found this in some physics journals where they write $1/2\pi$ to mean $\frac{1}{2\pi}$, not $\frac{1}{2}\pi$.

Is there an actual mathematical convention for this? Or is this just a style thing that mathematicians avoid by using fractions?