Read the Pprune for hysteria!
OK just me over-reaction. If people posting here cannot maintain their position at something more than 100m and less than a mile I hope they spend most of their time at the keyboard rather than in the air!
My friends and I have done a fair amount of flying in company. With simple agreed instructions and a bit of discipline it is straight forward, fun and makes for an interesting trip. As for dooming people to collision and death - get a life!
The important things are to have that sset of rules arranged, to ensure that if people don't or can't follow them there is an agreed fallback and its pretty easy.
We started doing it beause only 1 of the 3 aircraft had a transponder and with the welcoming attitude of many 'international' UK airports getting a transit was tricky. Adding the magic 'formation' to the call usually got us through! We still do it from time to time although now there are lots of (becoming obselete) transponders between us.
Stick to a spot - which the lead aricraft can see - typically 4.30 at 500m plus. Follow the leader! Especially on the radio! After the initial joining call split up and adopt line astern at suitable spacing - from there on its one your own - individual coms with the tower. Joining up - agree where and what height, breaking up agree either a frequency to call on where the others will know what your intentions are or another method.....