You will be fine with a SAK anywhere, even in the UK.
In the UK, locking knives are illegal unless you have a "valid reason" to carry one, such as if you are on the way to or from a job where a knife is essential. From reading British Blades, I gather that even carrying multiple slipjoint knives or multitools is frowned upon. I believe you need to have a blade under 3" but I could be wrong.
In Florida, you can carry just about any knife and any size you wish, fixed or folding. The laws are kind of weird about it, but over a certain size you must not carry it concealed (part of the knife should be visible, such as pocket clipped).
In NYC you must not be able to wrist flick or Spyderdrop your knife (tighten the pivot), but you are able to carry a fixed or folding blade of up to 4". It must be single edged and should not have any spring action. No butterfly knives either. You will not be able to bring the knife into any touristy locations such as the Liberty Statue or the Empire State building, although pretty much all museums do not have metal detectors and do not care about knives in your pockets. Knives must be fully concealed to be considered legally carried, not even a pocket clip must show. So carry your knife deep in your pocket or clipped IWB.
Vegas, it seems the blade limit there is about 3" or 3.5". Casinos do not care about your knife, and if they see it they will ask you to put it in your pocket instead of clipped.
