Its not a problem at all... its sitting on the forks normally.
Maybe you should think about the abuse you put it through on the road... you probably generate a ton or so of load on the front and rear just riding over a speed bump normally and hitting potholes or manhole covers at speed probably twice that amount...
When you're blipping hard under brakes most of the engine oil is right at the front of the sump and you're generating phenominal loads inside the engine as the revs shoot up.
Seriously, when they're moving they're subject to forces that you'd never even dream of. It doesn't matter too much how you sit it when its stopped so long as you don't kick it over on its side
