Part of the ongoing Verse Quick Reference project.
Pro 16:33 The lot is cast into the lap, but its every decision is from the LORD.
Calvinist John Piper includes this text in a list of prooftexts on God doing everything that ever happens:
God “works all things according to the counsel of his will” (Eph. 1:11).
“All things” includes rolling dice (Prov. 16:33), falling sparrows (Matt. 10:29), failing sight (Ex. 4:11), financial loss (1 Sam. 2:7), the decisions of kings (Prov. 21:1), the sickness of children (2 Sam. 12:15), the suffering and slaughter of saints (1 Pet. 4:19; Ps. 44:11), the completion of travel (James 4:15), repentance (2 Tim. 2:25), faith (Phil. 1:29), holiness (Phil. 3:12-13), spiritual growth (Heb. 6:3), life and death (1 Sam. 2:6), and the crucifixion of Christ (Acts 4:27-28).
Piper, John; Taylor, Justin; Helseth, Paul Kjoss. Beyond the Bounds: Open Theism and the Undermining of Biblical Christianity (pp. 380-381). Crossway. Kindle Edition.
In this sense, Proverbs 16:33 is used to illustrate God’s meticulous control over all things. Granted, that is one such possible meaning of this verse, but it is not the only meaning. Language is not that static that a simple sentence without context must mean what Piper claims it to mean.
Adam Clarke takes the “lot” to be a serious inquiry to God, and not to be confused with playing with dice. Other possibilities include this proverb being a generality, or just illustrating a concept such as God is the one who guides people. The author is unlikely to be claiming that for a pair of 6-sided dice, God just prefers that they roll a 7 most often, and other numbers according their own random probability.
Proverbs lacks context to clarify the meaning of this passage. Just a few Proverbs later, the author talks about God testing hearts to know what people will do (Pro 17:3) and being angry at people that do wrong (Pro 17:15). The author might believe that God guides people’s paths, but in a responsive way in accordance to what God observes in human behavior.
God is Open 
My notes on the verse:
In old testament times, it seems, God would answer people’s inquiries by lot-particularly the lot cast by the priest using the Urim and Thummim. The priest did something with those two stones that was totally random. The outcome was either “yes,” “no,” or “no answer.”
1Sa 14:41
41 Then Saul said, “O Lord God of Israel, why have you not answered your servant today? If this guilt is in me or in my son Jonathan, O Lord God of Israel, give Urim; but if this guilt is in your people Israel, give Thummim.” And Jonathan and Saul were indicated by the lot, but the people were cleared.
(NRSV)
1Sa 14:19
19 While Saul was talking to the priest, the tumult in the camp of the Philistines increased more and more; and Saul said to the priest, “Withdraw your hand.”
(NRSV)
1Sa 28:6
6 When Saul inquired of the Lord, the Lord did not answer him, not by dreams, or by Urim, or by prophets.
(NRSV)
Today we should not depend upon lots to glean the Lord’s will. It was true even in old testament times that it was better to know God’s character and thus know his will. By knowing God’s character, a person becomes a partner with God in shaping new things-through prayer and actions that are consistent with God’s character.
We should have the mind of Christ (1 Corinthians 2:16).