You can check Google Maps app, for example. But any other app works, too.
That's not what I meant. That requires me opening the app, activating GPS, and allowing it to track me.
You allow the application to access the GPS information, but your phone vendor probably knows it all the time. If you even allow a single app to use it, they know. Because just the GPS data doesn't help much; it's usually sent to Google / Apple servers to e.g. show your restaurants in your vicinity or for being able to find your phone if you lose it.
Even if you turn off location access for every single app, and even though the Android kernel is a (open-source) Linux kernel, you probably have a ton of closed-source vendor stuff in there (iOS is fully closed, of course), so there's not really any way to tell that that GPS data never leaves your device.
Best would be a hardware toggle or ability to remove GPS and WiFi (also used for location sensing) antennas, but I'm only aware of laptops that allow to do this.
dkbit98 said Google knows my current location and shares it with anyone who asks. I would like to see where this info and location sharing is happening. I am not delusional and know that everything you do on your phone leaves digital evidence and you are tracked through every possible sensor. But if it's that easily accessible, I would like to see it.
Oh, now I got your question. Well, as far as I know there are some new data protection laws that mean (at least in the EU) they're required to hand you all the personal information they have on you. For Google there's a section in your account settings where you can request it. It also includes search history and such things.
Regarding sharing of any information they have about you; check the terms of service of their products and I'm sure all of them include something like 'we have the right to share (anonymized?) information with third parties'.
I am happy to report that my Google Timeline is completely empty. According to Google, I have never even left my house and I am planning to keep it that way. No movements in my town, I have never travelled anywhere, visited any new cities, and they have no photos to connect me to any destinations. The less they have, the better.
Wow; that's amazing! I fully understand if you don't want to disclose which exact phone you use, but is it degoogled or modified in any other way? Does it run stock Android or something like Samsung launcher (which might collect location and other information & share it with Samsung in this case instead of Google)?
In reality, Google only claim they don't collect your data by not showing anything on Google Timeline. They still track you even after you opt-out[1], although AFAIK their ads/recommendation become less accurate after you opt-out.
This is why you should never trust a software trigger. I never trust my phone with the Wi-Fi disabled or 'Airplane Mode'. It is just a button on a display. Same with Google. It may remember your choice, but it does not mean it will stop doing tracking you just because you said no.
Sure; I recommended hardware toggle earlier, too, since there is always some risk that they leave stuff on even if you turned it off, or collect information and tell you they don't have any, and such. It would be bordering on fraud in my opinion; but still being 'better safe than sorry' is always a good bet.
I might say stupid things right now so someone chime in if that is the case. Say you had a Bitcoin NFC 'Hardware Wallet' on you.
[...]
I believe the OP's question has been sufficiently answered, but I wanted to chime in, since you asked for it..
The original question is about RFID, not NFC; the two don't really have anything in common except maybe being both wireless communication systems. You can't track a NFC-capable wallet with RFID technology, but you can perform NFC tunnelling and other attacks (that's another story).
However, it appears to me his question was actually based on the belief that since Bitcoin is digital, Bitcoin wallets themselves can be detected and tracked in the real world through RFID technology. This is absolutely hilarious, since a normal Bitcoin wallet is pure software. So it's almost as if I asked 'can I check if you run Firefox or Chrome by RFID-scanning your laptop?'.