It's not just the Bed that determines if you meet the requirements for a raid. It's being within 40 meters of at least THREE base structures. A workbench, campfire, and standing wood torch are all that's needed to set off a raid event. The "You are being hunted..." (wolves) event doesn't even need that.
The Wiki lists like 25 items that count as "Base Structures" for determining if a raid event will trigger. Most of them are crafting tables or something that creates light/heat.