Teachme2play: 1st paragraph: That seems like an artificial way of increasing the length of the game. And it doesn't help. Does it really make the game more interesting if it goes:

A: 1 five
B: (anything)
A: 2 fives
B: (anything)
A: 3 fives
B: (anything)
A: 4 fives
B: (anything)
A: 5 fives

and now B says "LIAR" and wins the game, or bids and A says "LIAR" and wins the game? It just prolongs the game for 2 months.

2nd paragraph: Well, yes, I understand you think that's the smartest move for B. I wonder why, specially since the "mistake" you let B make seems like a brilliant move (given the not so smart opponent you let A be) to me.

3rd paragraph: I fully understand why you think the reasoning of B will be. I'm just pointing out that with such a reasoning, I expect that out of 100 games, I will win 99 of the games against B. For instance, against such a B, and with the roll 2,2,5,5,6 (so, 5's instead of 4's), I could have played exactly as you let A play against B. B is tricked in believing I don't have any 5s, calls LIAR, when there are indeed 5 fives.

Would you play "6 fives" having no fives on your hand, hoping opponent has 4 fives?
You're failing to understand my point. My point is, if I had 2 or 3 fives, I may not mention them until "5 fives". Clearly, with the B in your example, that's a garanteed win (he'll call LIAR based on my not mentioning them before).