I normally almost never pre-register for a race, even the heavily promoted pre-reg benefit of this weekend's I still did not pre-reg. I don't have a good reason for not pre-signing up because I race about every race I plan on doing, maybe I have a hard time committing or want the option to bail (even though I almost never do) or there is really very little benefit for doing so.
HOWEVER, there are good reasons for signing up for the Boulder Cup races. These races have huge turnouts and given the popularity of CX these days you don't want to miss out due to field size limits. If I remember correctly registration times played a part in the callups last year however according to the website it is not certain if that will be the case this year
"ACA Categories Call-ups will be based on top 20 BCR ranking. After that promoter discretion. UCI categories - Call-ups for the Elite Men and Elite Women based on current rankings as posted on the UCI Website: www.uci.ch"
All information regarding the races start from the DBCEvents.com website