Yes you can get misting by penetration.
The silnylon used by TT and SMD (and others...) is rated at 1200mm , that means it can hold a column of water 1200mm high without leaking.
If the rain drops are large enough they build up more pressure than the 1200mm rating can hold.
Not common at all but it does happen.
BTW, there are several other tent fabrics in use that (inc Epic and polyester) have a rating between 800 and 1500 mm (31"-59")
Polyester has usually a PU coating. The thicker the coating the more waterproof it becomes but the heavier it will be.
PU coating also weakens the fabric and it can (and eventually will) perish, ( the sticky/smelly tent fabric you read about)
I did some tests with the TT sil and verified the waterhead.
Just to try it , I painted a very thin coat of silicone on a piece of the fabric (much higher dilution then when seam sealing) that took the waterhead to about 2000mm.
But I have not bothered doing any of my shelters with that.
Franco
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