Hand #20 today (Aug 10, 2018) at Adventures was interesting. You (West) are dealer with ♠K9742 ♥K87 ♦— ♣AQ985. With a minimum hand and 5-5 in the blacks, opening 1♣ (and planning to bid spades twice) usually works out better than opening 1♠. With a good hand, you do not mind opening 1♠ even if you end up making a “High Level Reverse” with 3♣ over a 2♦ or 2♥ bid by partner. So, you open 1♣ and partner responds 1♦ (of course!). You bid 1♠ and partner bids 1NT. You then rebid 2♠ and partner passes. The lead is the ♥4 and Dummy produces: ♠J3 ♥AQ4 ♦J109632 ♣76. Partner is aware that you might have the weak 5-5 hand, although you could have six clubs and only five spades. However, it is matchpoints and she will not risk going to the 3 level in your minor in case you are only 5-5.
The hand is extremely friendly. Your best course is to take heart on Dummy and immediately take club finesse which wins (with the Jack falling on your left). Then cash the ♣A (with 10 falling on your left) and play another low club. North will probably discard a diamond. Ruff small on Dummy. Heart to your King and another low club. If North discards, ruff your club and cash the ♥Q. Then ruff a diamond to your hand and start giving up spades. Since spades are 3-3, you cannot lose more then three spade tricks. If LHO gets impatient and ruffs in front of Dummy with the ♠A and leads a spade, you will lose only two spade tricks (and one club).
In this particular hand, you would get out at 2♠ even if you opened 1♠ as partner would bid 1NT (Forcing) and you would rebid 2♣ and partner would take “false preference” back to 2♠. However, give partner the ♦A along with the rest of her hand. Then, if you open 1♠ and partner rebids 2♦, what are you going to bid? Rebidding your anemic five-card spade suit should make you sick to your stomach. Bidding 3♣ would be a High Level Reverse showing about a King extra in values (15+ HCP).
That is why with the “Baby Blacks,” you open 1♣.