The geolocation is dependant on a third party agreeing you are in a specific location. So if for whatever reason apple (in the case of iPhones) does not agree you are in the geolocation of your home, you will be unable to access your coin.
Which is not unlike 2FA with Electrum wallets, or any web wallet or exchange in existence. I don't use these services and I don't want a third party to have any say whatsoever in how I spend my coins, but you can't deny that there are millions of users who do use such services. And you can always recover your wallet from your seed phrase and bypass the geolocation entirely.
Sure, there are always risks when using third-party services. The difference in my eyes is that Coinbase (for example) is in the specific business of handling coin on behalf of their customers, which includes processing crypto withdrawals. if Coinbase screws up too much, they will eventually go out of business.
Relying on geofencing on the other hand will rely on your phone's GPS. Apple is not in the business of handling their customer's coin. They are not even in the business of providing precise location data to phone owners, or even location data in general. It is also possible that your phone's location is currently wrong, and when this gets fixed by Apple, your phone will think it is not in the correct geolocation when it is in the intended correct location.
Or, an adversary could steal your phone and take it it to your front yard in order to steal all of your coin (without even having to break into your house).
I had assumed the geolocation was in addition to the usual security precautions of a password/PIN, not in place of them.
Fair enough. Although if your security model is that you need a geolocation in addition to a PIN, you are assuming a PIN is insufficient.
There is also the risk of tricking your phone that the price of 1 bitcoin is $0.01, which would allow an unlimited amount of coin to be spent.
I don't understand where you are coming from here. Just set the geolocation to restrict to x amount of bitcoin. Or as in my proposal above, geolocate restrict a whole wallet while keeping another wallet free.
For some reason I was thinking the amount allowed outside of a particular geolocation would be $50 in
BTC. Fixing the amount to x amount of BTC, rather than $x worth of BTC would address this issue.
It would be very ill-advised to prevent someone from being able to spend all of their coin that is in their wallet unless a criterion is met (being within a geofence) as they could potentially mean the end-user is unable to spend all of their coin.
What about this?
Regarding something like servers breaking, phone GPS sensor malfunctioning etc., keep in mind you could always have either an emergency passphrase or directly use the seed words to restore that wallet in e.g. BlueWallet or Electrum.
Just restore from seed maybe?
Yes, that would work. Although you would need one additional backup if you were to rely on this.
I do think a LN wallet with a channel open with your home computer that automatically sends/receives a LN tx when you leave a location would be best. If you have the private key to the address where your phone's channel will end up at when the channel is closed, you can simply broadcast an old channel state if you lose your phone.
