Right after the IT-alert the quality of my mobile internet connection plummeted for almost an hour, my ping from Italy to Netherlands was between 100 and 600ms (usually it's 30-55ms).
My guess is that some people weren't aware of the test and started calling their relatives asking questions.
same in germany around the 1st. was at a store with friends from the US and china. Everyone one's phones started to ping. Even the US and china ones on roaming (or local sim cards? don't really know)
However i am assuming that the european alert standard is based on an earlier protocol than LTE, does anyone have any info?