And I can't take it back
As I wrote about in the post about my THEO account, I broke down and submitted my My Number to them.
The reason I did this is that without it they would not have opened the account.
I am still reluctant to use My Number if it can be avoided (you can read about my concerns here, here, here, and here).
So I guess this will be my policy going forward. Give out the number in situations where I am the weaker party and need to get something done, and refuse within existing relationships (like with my employer or current bank).
I'm sure I'll be writing about this again :)