Non non, c'est bien deux choses différentes :

Some folks have suggested that the problem could be due to conductivity. They’ve suggested that the moisture on people’s fingers may cause a current path between the two pieces of metal. This is possible, if it did happen it would certainly cause big problems. Some folks on the internet have put a coin across the gap and showed that this causes performance degradation. However, there are some videos now showing the problem occurring with iPhones in rubber and plastic cases. These cases are unlikely to conduct well at GHz frequencies, so I think the dielectric explanation is more likely.