What counts as maintenance staff? The above answers seem to imply that only janitors would fall into this category but staff electricians, HVAC engineers, etc are often part of the maintenance crew in lots of shops.
Lots of larger enterprise DC's I've had contact with have actually specifically excluded the majority of IT staff - to include senior systems and network engineers, etc. The idea is that a very specific set of DC facilities/operations people should be sufficient to physically operate the infrastructure without particular non-facilities domain experts being allowed into a space that they're often not qualified to be in anyhow.
It's actually only in the smaller facilities that I've seen sysadmins typically involved in standard rack-and-stack / cabling. Some network organizations keep their hands in longer, but even they end up splitting off day-to-day cabling (and even a lot of the layout/design) to dedicated facilities people. I've generally just chalked this up to the greater need for specialization.
BTW - Dedicated DC facilities orgs will often have their own specially trained cleaning staff. There -is- need to keep these areas clean over time, albeit through different means than standard office space.