Even if you didn't have exactly $1 left in your BR/online account, use approximations. If one day you had $100 and the next you had 0, that would count as well.
Once IRL; but I had a $400 check in my PO box that I didn't know about. Still, it was like I was broke.
Online, never. I just get nittier and nittier as the account goes down. Once I had a $5 balance in Bovada and they took pity on me and sent me an email to the effect of "Dude, we put $5 in your account, no strings attached, now go make us some rake you ridiculous nit." And I did.
Quite a few times but one memorable one was when I was all in at PLO10 deep for my last 40 cents. I trippled up before going on a heater where I ran those last few pennies to 1k over a couple weeks before losing it all.