-snip-
Thats extremely far fetched. What are the chances?
A laptop with wifi turned off (dont even need to remove the actual card for fuck sakes) will be safe unless you are someone like fucking Asagne or something.
100% is extreme, yes.
Whats the best DBAN method to use? PRNG stream?
For a magnetical HDD it does not matter nowadays. The old 7 times "rule" was made for disks with a wider track. Thus you can overwrite the disk with any data, 0's, 1's, random bits, your favorite dog pictures.
Edit: you could test how good DBAN works with DEFT [1]
[1]
http://www.deftlinux.net/