In reply to philip king: i said i would never post again unless using my real name but changing user name is an arse..anyways..
Below is the info from the wiki but firstly in answer to your question; people bolt things sportingly for two reasons. 1. Because they don't want to or can't afford to spend money on bolts(mainly back in the 80's and 90's). 2. To make the route a little more exciting with more of a run out trad feel to it despite the bolts. This was taken to the extreme in the quarries particularly on the Rainbow slab.
'Gorbals E4. New bolts the first bolt was lowered and the RURP replaced with a higher bolt, another bolt was added below as the rock is friable, and although there is gear it is all behind loose flakes, another bolt may well be added to the start because the gear was poorer than initialy thought when it was re-equipped and Lower off. 10/06'
Lovely photo's by the way Mark, seems like alot of folk have enjoyed them too. nice one. Jon Ratcliffe