Good point, was just going to post this myself, you beat me to it. A hint
should be added to the web2py book in chapter 5
http://web2py.com/book/default/chapter/05?search=block#Blocks-in-Views
something
like:
The *{{block}} {{end}}* construction *cannot be used* inside a python
condition specified by *{{if some_condition:}}*. The current implementation
will ignore the condition. But you can use conditions *inside* a *{block}}
*construction or
use the {{def}} construction.
I've added this to the web2py book as a comment. One of the editors will
process this.
Nico