In my account I have 2 campaigns for a company. One displays ads in the UK, one in the US.
The reason I have separated them is for tracking purposes - I can see how conversions for the clicks from US visitors compare to UK.
So, will my UK ads always show up for a search for 'widget' if on a UK IP address - or will Google alternate between the 2 campaigns, realise the US one is not relevant and just show nothing (i.e. show my ads 50% of the time in the UK)
Cheers,
Neil