I'm worried because Google tells me my smart phone was used to access my Google account from Brazil a couple of days ago. But I and my phone have been in the San Francisco Bay Area the whole time. (Note: Google find phone does not use a cell phone tower location, but judges by ip address location)
Two possibilities have occurred to me:
(1) Opera Max (a VPN which offers a free data compression service) has been running on my phone for a few weeks - at least I hope it is Opera Max. Could it be that Opera Max allocated a temporary IP Address located in Brazil as part of the VPN service? There are no other locations besides Brazil showing up, but then again Google only showed "recent" locations, without being specific about how long "recent" is.
(2) Somebody has created a doppleganger of my ATT sim card, and is using it from Brazil in an attempt to hack me and steal something. I'm planning to go down to ATT and change my Sim card.
If anyone has had similar experiences with their phone accessing IP addresses in unexpected distant locations, or knows anything about this subject, I would be grateful to hear about it.