I've tried both of these devices. The Digitone (and anything similar) is useless, as it requires you to press a button every time you receive a call from a "bad" number. I did this for about a week, logging hundreds of incoming calls, and I rarely saw a duplicated number. So you'll just be pressing the button all the time - might as well just pick up the phone and hang up.
The Sentry is much better, but has some notable flaws.
The Sentry works as a whitelist, so it blocks all calls by default. After you enter your whitelist (family, friends, etc.), you'll get three types of calls:
-Good Calls: From people on your approved list. These calls ring through as normal.
-Bad Calls: From idiots (aka robocalls). The idiots aren't smart enough to press a button, so they don't, and then the Sentry hangs up the call.
-Other Calls: From humans who are (ideally) not idiots, but aren't (yet) on your list.
This third item is where the Sentry really needs improvement. Other callers hear a (horrible quality) outgoing message, so they can either hang up, or press a key to leave a message - on the Sentry, not your answering machine/voicemail. The message they leave is only 20 seconds, and you can only receive two messages. And you can't screen these calls - you don't actually hear the person leaving the message, and you can't pick up the call if it turns out it's valid. And the Sentry doesn't timestamp the message. There's a log of calls, but you have to work to figure out who actually called, especially if the caller's message was cut off.
(What I would prefer is to have callers press a button, then my phone rings like normal.)
If you don't get a lot of "new" numbers calling you, the Sentry isn't bad. But you will miss some calls, especially at first. Thankfully, there's an on/off toggle for those times when you're expecting an important call from an unknown number (delivery guy, hospital).
Tracking - or the lack thereof - is their problem, not mine. I don't feel I should be obligated to participate in order to be notified that my account has been compromised.
And I certainly don't care about their "goal", whatever that is.
> I wonder if the issue might be some question about if the user is receiving statements or not.
Couldn't they just ask me? Then I could reply (or not).
> Perhaps another issue is a security check, such as a dormant or hijacked email that would otherwise expose itself by reading all their emails from another country unexpectedly?
A tracking beacon is no guarantee that I opened the email, just that somebody (with access to my account) opened the email, no?
Has the author never heard of introverts?