[Vwdiesel] Tattle tail plug in head?

[Shawn Wright]

Well, I got my head back today, a long story that I will tell later 
when I have pictures. But one quick question - they installed a 
"tattle tail" plug in the end of the head where the frost plug was. 
When I asked, they said it would give in by melting the centre if 
the head was overheated. I asked at what temp, and was told 
around 250F. 
Is this safe? It would seem to me that a sure way to warp the 
head would be for all the coolant to pour our when this plug 
pops! Ironically, it says "void if removed" on it... assuming this 
refers to a warranty, which of course I didn't get... (part of the 
long story).
I'm wondering if I should replace it with a standard plug. I'd 
hate to have this thing melt at 230F and toast the head...