I use Shimano M520 pedals. I love them, but, yes, I do occasionally unclip when skidding. This is because I have bad form and I accidentally twist my ankle while pulling up. Therefore, I unclip. When I do more pushing down, as opposed to pulling up, and I'm mindful of my form, I rarely have an issue. However, when I use toe clips and straps, I tend to pull my forward foot out 70-80% (maybe that's a bit of an exaggeration) of the time. So from my experience, there's no 100% solution.

If you do go with clipless pedals, go with MTB style, i.e. Shimano M520, or ISSI pedals. Choose something that will allow you to use shoes you can walk around in. Road bike shoes SUCK for walking around.