NO!

For all of the reasons listed above plus...

People generally consider their vehicle an extention of themself. Would you lean on or even touch someone in front of you in line at the grocery store?

Sure, you're not doing any damage, but it's still disrespectful of other peoples' property/space.

If you make this your common practice, sooner or later someone will retaliate... not worth it, unclip.

Don't do it.

Oh, did I mention it's a really bad idea?