Usermessages can occasionally be missed by the client due to what I'm guessing is packet loss. This happens from time to time in a plugin I'm running that blocks player chat in a say filter and re-sends it using the SayText2 user message creator.
Can we make all usermessages reliable by default? I'm not sure what the performance impact of that would be. Otherwise, a method or attribute on RecipientFilter to change m_bReliable should suffice.