Does anyone have any experience of this? I'm happy for people to tell me it doesn't happen but if it does, what do people do about it?

The first sign is normally a headache. Descent is the only viable cure.
Many people climb Jebel Toubkal on a two day ascent from Marrakech--first day Marrakech to Imlil, then start climbing and overnight at the refuge at 3000m, do the final 1200m the next morning, then decend and back to Marrakech.
Personally I feel this is too quick and would put another acclimatisation night in at Imlil (1700m), but having said that, I've not heard of anyone having problems.
General info: http://www.imlil.org
If you are just doing the normal main roads, none of these are more than about 2400m.
Edited: 8:49 am, February 25, 2011We had headaches about 100m above Imlil - locals called it altitude sickness and their remedy was plenty of Mint Tea! We are not used to mountaqins, living a sea level, and are not particularly fit, but the headaches went away after a couple of days. It is very dry, however, and dehydration would also be a factor in mountain wellbeing!
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