Carrying a spare key - transponder issues

Hello all,

So on my previous bikes I always carried a spare key when going on roadtrips as I am prone to lose important things once in a while, and getting stuck thousands of miles away from home without a spare would suck.

However my Tiger is the first bike I've owned with a chipped key, and I read that carrying the spare too close to the ignition will lead to potential glitches with the immobilizer.

Since my luggage is key-matched to the ignition, I can't simply keep the spare in a pannier... the furthest I could realistically keep it is my jacket's pocket.

Would that be close enough to cause issues? If so would wrapping the spare in aluminium foil take care of the problem?

Cheers.