Apparently some so-called next generation endpoint products were cheating, using VirusTotal to supplement their catch rates. Those vendors, who aren't contributing their engines to VirusTotal, have been cut off from using VirusTotal.
Links:
A bomb just dropped in endpoint security… and I’m not sure anyone noticed – Alex Eckelberry
VirusTotal Blog: Maintaining a healthy community
Intel Security at RSA Conference: 'Competition Is Holding Us Back' - Fortune