A circuit intended for an actual cigarette lighter will be robust, but ones intended for use only as a 'power point' may be far less so. They should still be adequate for 4 of the common dashcams and more anyway. The usual problems found here are inadequate cheap 'splitters'. I have a 30A direct-to-battery circuit and a real cigarette lighter socket to power mine. Going to add a couple more sockets soon.
A cheap way to create a "fat" circuit like mine is to use some economy jumper cables and a fuseholder at the battery. Cut the clamps off and wire direct with an appropriate terminal. These have thick insulation and they usually cost about half of what regular wire of that size costs. You may have problems finding a place to penetrate the firewall with something this big though. Be sure to fuse this as close to the battery as is possible, that much current shorted out equals huge amounts of smoke!
Phil