Posted 2016-November-17, 11:10
"Free bid" means "I could have passed and you would have had another call, you know, but I didn't". Frequently (more frequently in the Ancient days of 1950) this means "so take it that I actually want to make this call, and have more than I would have if there was no intervening call." It's not necessarily forcing (like here, I wouldn't expect it to be forcing).
Here, you could have passed and bid 2♥ after the reopening double, which would have shown less. But you didn't. And GIB knows that.
When I go to sea, don't fear for me, Fear For The Storm -- Birdie and the Swansong (tSCoSI)