I don't think it was wrong. I just think it was purely symbolic as opposed to strategic. Both approaches are valid. It all depends on if an ardent Fred supporter thinks knocking McCain back in MI will help Fred elsewhere, or if he thinks the final MI counts will be more valuable by having a decent showing.
As I wrote above, you makes yer vote and takes yer chances.
I also tend to wonder why it is looked so badly upon when John McCain gets crossover votes (ie. voters that may or may not support him, but voting strategically) yet it is encouraged for Mitt to get votes the same way?
I don't believe in open primaries. If you want to nominate a Party candidate, join the frickin' Party. If a candidate can't win without crossovers, then he is a piss-poor representative of the Party.