I've got to find out that there are some profiles that have received whole lots of merits but some of those profiles don't circulate their sendable merits to others profiles thereby allowing the sendable merits to decay and become worthless.
How did you check it? if you only check by clicking their merit history, it's not accurate because the forum only show last 120 days activity. Moreover it's the user's right whether he want to spend his sMerit or not, there's no obligation sMerit must be spend.
Even though it was mentioned unused sMerit could be decayed by the administrator, but there's no proof someone claimed if his sMerit got deducted.
Yeah this sM merit decay issues has been on discussion for some time now and least I could say is that it is the sole right of any user to distribute his or her sMerit or not, however I don't think the sMerits decaying process has been implemented because no has seem to have complained about a missing sMerits.