Most Helpful Guy
It might work, but there's also a chance he sees that and says "time to move on"
Most Helpful Girl
It's a bad idea. Playing games never works out because you don't know what his reaction will be. He might see the other guy and assume for you it's a casual thing with him and so he'll start hanging out with other girls too. Or he might like you and see you with another dude and feel betrayed, like you're cheating or something and then dump you altogether. It's really not worth it. And just because the idea of him being jealous is ego boosting or some assumed indicator of his feelings, that's just a stupid fantasy instilled by pop culture. That isn't real. Think about it, put yourself in his shoes. If he showed up with another girl how would you feel? Wouldn't you just feel hurt or disappointed rather than jealous and trying harder?