Does anyone know if the magnets in magnetic tank bags are dangerous to electronics (laptops, tablets, phones, etc.)?

I am looking at getting this bag and was wondering if anyone had any definitive experience.

No, your personal electronics will be safe.

In the 90s we had it drilled into our heads that magnets were bad because they could damage CRT monitors and magnetic floppy disks. Neither of these technologies are in common use today. Mobile devices use LCD or OLED displays which are immune to magnets, as are the newer storage technologies like SD cards and SSD hard drives.

If your laptop still has a magnetic spinning disk, it's possible that a strong enough magnet could cause corruption. However in practice it's very unlikely. The magnets in that tank bag wouldn't be strong enough, if they were it might damage your tank. Also, a laptop large enough to have such a hard drive would probably be too large to fit in that bag.

There is, however, at least one important item which IS still vulnerable. The magnetic strips on your payment or ID cards can still be wiped (but not NFC, RFID or smartcard chips). Keep your wallet away from those magnets. 

Edit: Don't forget, many passports also have a hidden magnetic strip in the cover. Keep your passport away form magnets as well, unless you've already upgraded to an RFID model, in which case buy an RFID-blocking sleeve for it.