Dont mean to be rude, but to a degree what you ride may have a bearing on this. If you are on something like a 15 yr old hack, then I would say dont bother, if however you ride is something shiney, new and very desireable then yes I would, but as has already been said on here, if they want it they will get it.
Personally I always carry my chain and lock, then always chain the bike to an imovable object, lampost, cycle rack, copper!!!! Thieving bastards think nothing of picking the bike up and slinging it in to the back of a van if you just chain it up free standing as it were, my friend had his CBR600 dissappear that way. Then they can take their sweet time getting the chain and locks off in some grotty back street shed.
Touring tips in general: dont set yourself silly targets, remember the journey is the holiday so enjoy the ride. Dont look at a map before you go and tick off trophy towns, (got to get their at all costs) you will see nothing.
Travel light.. a few thin layers are better than one thick one.
Every couple of nights make sure your room will have a hairdryer. how else are you gonna dry your skiddies by the morning.
Get yourself some vacumn bags, they compress clothes to half their original bulk, dont forget one for the dirty washing.
Bin it... dont carry half empty bottles of shampoo, shower gel etc, dump it and buy more at the next overnight stop, whats it gonna cost you for the duration £10 at most.
Tell her you are travelling light... that means only 10 pairs of shoes (none of which she will wear) only three spare handbags (none of which she will use) only half your daily makeup,perfume,face cream hair tonic,nail polish, ( none of which she will use) only 12 tops, 15 skirts, 5 pairs jeans and 8 wooly jumpers (none of which she will use)
Oh and watch out for the men up there, heard tell they wear skirts and no knickers, strange lot....