Something that they rarily allow and together with some other bloggers they showed us (amongst other things) their silicon hair springs and what kind of abuse it was able to process without breaking or deforming.
Before that visit, I didn't think anything of silicon and just noticed that a number of watch manufacturers started to embrace this material in their watchmaking. I've seen the discussions in Revolution Magazine and other publications, talking about whether it is a good or bad thing to embed silicon into traditional watchmaking. However, I never formed an opinion on it myself until that visit at Nivarox.
I can imagine that purists of haute horlogerie could be a bit bothered by the use of silicon. This material is high-tech, the fabrication of all silicon parts is a very modern process that has little to do with traditional watchmakers fiddling with tiny parts at their workbench. Also, all parts have the same characteristics, so there is probably little pride in it for these master watch makers working on haute horlogerie timepieces. You could say a silicon part is just a part with always the same parameters. Last but not least, the material looks quite different from what you are used to when having a close-up at your watch movement.
However, when it comes to brands that produces watches that are meant for every day use (some times a life long), I applaud the use of silicon as it is not disturbed by magnetism and handles (little) shocks better than metal springs which can deform or break. For an everyday mechanical winding watch, I see only advantages. Brands are so confident about this technology, that - for example - OMEGA has increased their warranty period from three to four years for all their watches using a movement that has a Co-Axial escapement and a silicon balance spring.
I am not afraid that the use of silicon will depreciate the Swiss watchmaking industry as long as watch manufacturers are aware of the effect of these high-tech materials in watches on watch consumers. Would consumers of Rolex or OMEGA (or other watch brands in that category) watches care about the silicon parts in their watch? (e.g. only few cared about the nylon part in an Omega Speedmaster Professional hand-wound movement or about the use of plastic parts in a Lemania 5100 movement)
Would a Patek Philippe, Vacheron Constantin or Audemars Piguet consumer care about the use of silicon parts? Probably more than the consumers of the other group but it probably also depends on how the message is wrapped (or marketed).
In the end, the consumer decides whether the use of silicon fits into traditional watchmaking and the watch industry is hopefully very well aware of that.