Yes, I've seen that. On March 13th one of my sites has acquired 4 or 5 sitelinks. On March 15th Google's traffic went down massively - to 1/10th of normal. On March 20th sitelinks disappeared. I'm still wondering what the hell was that with sitelinks? If it was supposedly a good enough site to give it sitelinks, why slash the traffic? Not so scare you or anything, just giving you another data point on sitelinks' quirks :)
Inbound links freeze has been mentioned here since March many times and I would say that I personally see that, too. In fact, I see it both ways - from early April on I've acquired some good editorial links that should supposedly at least result in higher G*bot activity or, better yet, bring some more traffic. None of that happening. On the other hand, on another site I've lost a very good link because of the linking site's structure update and that did not negatively affect anything either.