stock IsRPName(const name[], max_underscores = 1)
{
    new underscores = 0;
 
    if (name[0] < 'A' || name[0] > 'Z') return false; // first letter != capital
 
    for(new i = 1; i < strlen(name); i++)
    {
        if(name[i] != '_' && (name[i] < 'A' || name[i] > 'Z') && (name[i] < 'a' || name[i] > 'z')) return false; // a-zA-Z_
        if( (name[i] >= 'A' && name[i] <= 'Z') && (name[i - 1] != '_') ) return false; // unneeded capital letter
 
        if(name[i] == '_')
        {
            underscores++;
            if(underscores > max_underscores || i == strlen(name)) return false; // more than defined underline
            if(name[i + 1] < 'A' || name[i + 1] > 'Z') return false; // no capital letter after underline
        }
    }
 
    if (underscores == 0) return false; // no underline
 
    return true;
}

if(!IsRPName(name, 1))
{
                SendClientMessage(playerid, 0xDE5454FF, "You don't have a roleplaying name! Please reconnect using a name in Firstname_Lastname format!");
                SendClientMessage(playerid, 0xDE5454FF, "Make sure the name you choose is realistic, one you would use in real life! (i.e. ''John_Smith'')");
                SetTimerEx("DelayedKick", 450, false, "i", playerid);
                return false;
}