If true, that's a shame - I'd hoped that they'd enough supervision and monitoring to keep product safely. I'll quote this again in https://www.cyclechat.net/threads/the-cyclechat-helmet-debate-thread.187059/Decathlon, who use a column of boxed helmets to make goalposts for the Sunday late shift warehouse footy game? I don't expect any shop staff on or close to minimum wage to treat the merch with kid gloves behind the scenes.
I can't check it over sufficiently for damage which could render it worse-than-useless - even the manuals say "damage may not be visible" (Giro) or "in the event of any impact or blow, do not use this helmet. There may be damage invisible to you, which may reduce the ability of the helmet to reduce the harmful effects of a blow to the head" (Specialized). Helmet users are effectively trusting the supply chain with their heads.You can check it over when it arrives for any sign of damage, if your not happy you can return it for a full refund.I've had hundreds of items off Ebay and nothing to date has arrived damaged.
I've got a Specialized Max XL which fits my big head nicely and doesn't look like a mushroom perched on top either. Evans currently have them at £30.