Shrink art in a gas oven - what's the worst that can happen?

[VermicularCanister]

In searching for non-messy craft activities for DSs birthday party, I thought I had the perfect answer in these shrinkie keyrings.

In the blurb, it specifically says they should be shrunk in an electric oven. But we only have a gas oven.

Is this a health and safety thing (flammable plastic?) Or will they somehow go disastrously wrong, and leave me with a room full of disappointed 5-year-olds?

we are always doing crisp packets on a very low heat, i just make sure that they are on tin foil. not had a problem yet.

We did them iin our gas oven, just make sure you have something to hand to squash them flat afterwards (I used a chopping board) as they do curl up a bit.