My MyWi Question (BUSTED)

[maxwellsteel]

I've been tethering with MyWi for a long time to my Sony laptop from my iPhone 4. I've downloaded Gigs of data with my unlimited AT&T plan. Just last night I tethered to my iPad to download an app for the first time ever. I noticed a figure eight like symbol at the top of the iPad and wondered why there wasn't a wifi symbol. I didn't think to much about it till tonight. I got an email from at&T that said I had been thethering and if I don't stop they will put me on a plan or if I want to tether to choose a plan.*
So my question is, did AT&T detected my tethering because I connected to the iPad for the first time?*Were they not able to detect my tethering on the laptop?

P.S. I guess this is the end of my thethering days.
Thanks for looking

 

[maxwellsteel]

I figured it out

 

[sherlock]

I figured it out

Enlighten us?