How many vegan cyclists does it take to mount a rocket launcher on a tandem bicycle? How many ganja-puffing dog walkers does it take to launch a suicide attack on the Olympic stadium? What are the chances of a dirty bomb fashioned from old bicycle clips making it as far as the velodrome from outside of the perimeter fence?
All questions that the Olympic organisers must have been asking themselves before they closed off the towpath of the River Lea Navigation, where it wends past the Olympic Park at Hackney Wick.
Mystified and dismayed, cyclists and other users of the route have been staging protests after the decision to close off the vital section, that would have allowed locals to cycle to the Olympic games without going on roads or clogging up the bus lanes.
There is consternation that a section of the river that has been especially poshed up for the Olympics has been shut off at the last minute, apparently for "security" reasons. I have spent the last week wondering how on earth security could come into this. There are many other parts of the park where the perimeter fence is easily accessible to unscreened members of the public. And the fence is 20ft high, for Tom Daley's rippling sake.
Perhaps they wanted to prevent a Mumbai-style water-borne attack by canal barge? No, it still doesn't make sense - they would only have to guard the locks, not close off the whole pathway.
After much reflection this evening, I have reached the only conclusion possible: It is because the section that is blocked off comes dangerously close to the massive international press centre? Should Fathers for Justice or the We Hate The Olympics Its Shit And Give Us Our Money Back pressure group form a nasty flash mob in front of the world's press....
Yes, the prevention of angry protest and the ensuing international public relations disaster is the only explanation. We simply can't have a repeat of those regrettable riots where many poor people became terribly angry.
Ironically enough, it was by this very route that I was planning to cycle when I start work as an Olympic volunteer next Friday. My new route into the heart of the East End will be circuitous, dangerous and no doubt involve collisions with melon salesmen, two workmen carrying a large sheet of glass and a lorry dull of hay bales.
This, on top of a somewhat inconvenient new controlled parking zone in my street and an unsolicited "Olympic camp" on my local playing field.
Being a "critical friend" of Locog hasn't been easy in recent months. As I practice my welcoming smile for the capital's thousands of foreign guests, it is starting to look a little strained. Indeed, a little constipated, as I contemplate the arsey inconvenience of it all.