Genuine question: what else do they do, generally? Presumably even if they're not doing the standing-on-the-grid bit they won't be out of work?
I wouldn't want to generalise to the extent that I'd say all of them would have a lot else to do - it would appear to vary by person, team and series. Some just get the call, stand there for a little while, earn a bit of money and go. I've seen lots double up as promo/leaflet girls for sponsors about the circuit, some getting involved with the smiley smiley, laugh and nod side of hospitality (only had hospitality twice). The only time other than when they line up on the grid, that most people will really get to see them is the pit walk or autograph sessions, where again some will just stand there smiling, others will get more involved in managing the crowd and drivers in what can be a chaotic situation....
None of this is something that has to be done a pretty girl in lycra, but they are there and you know as well as I do,
a lot of camera's get pointed their way* so it's a great opportunity to get sponsor/team logos in the media... I think it depends on who organises the girls as to what else they do, to be fair in events like this (WEC/LMS), the only other thing I've seen them do is promoting sponsors and hang around smiling at VIP's, in series like WTCC and DTM I didn't see them do much more at all. but either way they'd be a truck load better than some fan-zone random pick autograph hunting weirdo (which is what some people are suggesting).
If you (the plural you - obviously not you personally, Furinkazen) want to see women not wearing much, well, you're on the Internet. The presence or absence of grid girls at race events makes absolutely no difference whatsoever.
Well, I understand how you see it that way, but I disagree, for me it's all part of the visual tapestry of a race weekend, not just an opportunity to see women not wearing much. I took 1480-ish photo's at Brands this weekend, about 28 were of grid girls... if I just wanted to see naked chicks I could just use the internet, but personally I like to have something other than cars to point the camera at.
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I typed out a really long rant here, but was getting so far off-topic....
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*... and that's really what it comes down to, getting attention. It's simply advertising, marketing, and branding. Grid girls are not even a secondary ripple of the drop in the ocean of women being portrayed, and portraying themselves, in a risque fashion to further either their, or their employers, bank balance.
Only 6 days until the best racing series returns!
Are any of you guys getting to Silverstone or indeed any WEC race?
Lucky you if so. I've got no friends interested in endurance racing so MotorsTV is as close as I'll probably ever get. I'd love to do the whole camper van trip to Le Mans someday.
Just realised this post sounds like a lonely hearts advertisement!
I'm there Saturday and Sunday, I live nearby so I won't bother camping. I've also got Le Mans all booked
.... but then I'm a reeeeeally boring bastard 
