Fair enough. As you go on to imply, I don't think that the issue you mention is likely to arise in relation to 'sensible' use of such plug, since they re clearly only intended for use with relatively small load.The fuse will have to be sized to support the total load from all four devices, this means it may need to be larger than the fuse that would be used if the appliances had individual plugs and in some applications may need to be larger than the current rating of the flexes.
Kind Regards, John