Is redirecting a large number of domains suspicious?

On February 26, 2009, Google software engineer Matt Cutts collected questions on Google Moderator and answered many of them on video.

cweave from Dallas, TX asked:

When permanently redirecting (301) a large number of domains (read: more than 10) to 1 domain does Google flag this as suspicious? What considerations does Google look at? For the purposes of this question let's assume this is a consolidation move.