We are required to disclose material facts and not to mislead the public, right? If the assessment is known about I would say disclose. Most HOA's have a provision for a special assessment in their documents though. On SPI you sometimes know about coming assessments through word of mouth
But, to answer your question...imo....yes, it should be disclosed prior to going under contract, as part of the listing.......whether that information is part of the MLS, or on another disclsoure is up for grabs.
I think that we should disclose them, because the objective isn't to get someone into a contract, the objective is to close a transaction. We should be marketing these condos to people with the cash to handle a special assessment, not getting a minimum-down buyer to tie up the property only to find that they can't handle the assessment.
To me, it's like marketing a fixer as "needing TLC." To heck with that - market to a contractor who has the ability to do the work!!!
Anyway - as buyer's agents, we should be able to scout around and look for warning signs of special assessments. EIFS, deferred maintenance, water damage under window sills . . .