Yes, because gel shoe inserts can model, in certain respects, shoe bombs, a la Richard Reid, the so-called "shoe bomber."

I flew out of Heathrow on Saturday and post security you could buy and bring liquids on the plane. BUT this was a flight to Ireland NOT to the US. I am not sure if there is second security for the Us

To my understanding these new relaxed rules only apply domestically, and not for International flights

I believe I read the regs apply to both domestic and international flights...the US regs were harder at Heathrow than the Brits...at Heathrow passengers were allowed to purchase liquids in the departure lounge and bring them onto flights except flights to the USA which I am sure was because of US regulations (the British would not want to hurt sales in their shops, how would they?)...I can't find any mention of the change on the baa site but I would suspect flying out of Heathrow will now allow liquids bought in the departure lounge onto US flights.

I stand corrected. The news on CNBC this morning stated domestic flights. I just called Continental and they state the rules have been relaxed to Europe also, with the exception of the UK.