Freddy Adu and Victor Palsson don’t have much in common, other than their incredulous reactions to be dismissed with second cautions during the past two weekends of MLS play.

They’d better get used to it. Though in both cases the incidents that prompted the second yellows could be interpreted as borderline situations, the referees are using cautions precisely as they are supposed to be: as deterrents to further infringements.

Rather than ignoring subsequent offenses by cautioned players, as dozens of MLS referees have done hundreds of times over the years, at least a few officials are ensuring that players get the message of what a caution is supposed to mean: Clean up your play, or you’ll be off. There are fewer occasions when an already-cautioned Landon Donovan – to cite just one example – could blatantly pull back an opponent by the jersey at midfield to stop a counterattack and stay in the game.

Adu, who’d received a first caution for scything an opponent’s legs with a very dangerous tackle, got a second when he veered past Red Bulls midfielder Dax McCarty in the penalty area and tumbled to the ground. From his knees he saw referee Jorge Gonzalez pull out the yellow card for diving, and then the red.

Palsson’s first caution was much like Adu’s, a reckless foul absolutely deserving of a caution. He’d also been warned by referee Ismail Elfath, yet couldn’t believe his eyes when Elfath came out with a second yellow after Palsson had clattered into Miguel Montano and knocked him down without getting a foot to the ball.

Of the two situations, Adu’s is the more murky, as he may have simply lost his balance when McCarty's challenge barely nicked him. It’s rare to see a referee warn a cautioned player but the referee is empowered to do so. However, Freddy’s flopping reputation is well-established, and while I don’t want a referee to send off a player with a second caution in a somewhat ambiguous situation, I also want the official to stand firm if he’s absolutely sure that a second yellow is warranted.

I hope MLS officials aren’t reverting to the days when waves of cautions handed out for diving, and too many bang-bang incidents in the goalmouth resulted either in a penalty kick or a card for diving. In a contact sport, there’s going to be contact, and sometimes the best call is no call.

What fans and pundits often forget is that a second caution, just like a first one, can be administered for persistent infringement. Again, too many times a cautioned player would commit subsequent offenses with impunity as if the first caution wiped the slate clean instead of putting the player on probation, so to speak.

It can be argued that dismissing a player and leaving his team a man down is too severe a punishment for cautionable offenses, but those are the rules. When officials are too reluctant to dismiss cautioned players who keep fouling, games can degenerate into free-for-alls, which of course trigger strident cries that the referee has lost control of the game.

In the case of Palsson, he’d also been warned by the referee in addition to being cautioned, and thus had no valid complaint – though of course he pleaded his case – when his very stupid foul prompted an early exit. The Red Bulls, playing 10 against 11, went on to beat Montreal, 2-1, anyway for their fifth straight victory, so not always does the punishment of dismissal doom a team to defeat. It did in the case of Adu, whose Union lost to those same Red Bulls a week earlier.

The officiating so far in MLS this season has been very uneven, which isn’t surprising, since a fair number of new referees have been getting their first experiences in league matches and a 90-minute match is a tough enough test for anyone. The league’s review process is handing out suspensions, such as Brek Shea’s three-game ban for kicking a ball at an assistant referee, that make very clear its intent to monitor closely peripheral incidents as well as those that occur during play.

A few stars aren’t monitored as closely and consistently as they should be: in recent games, David Beckham received a justifiable caution for barking at a referee’s assistant over an offside call – which was judged correctly by the way – but in another incident wasn’t disciplined for raking his studs over an opponent’s shin.

The proper and effective use of yellow cards is a vital element as a referee and his fellow officials administer and manage a game. Play-acting to dupe the referee into giving a second yellow is yet another nettlesome offshoot of this topic. Yet if MLS officials are taking a firmer stand regarding second cautions, it’s up to the players and their coaches to be on guard.