Very rare but you may have a hitter as 3and2 described that has a better chance of getting the bunt down than moving the runner otherwise or getting a hit. This may be a weak hitter who bunts OK but has a high K rate or a pinch hitter brought in who is a particularly good bunter but just OK hitter. Late in a one run or tied game with no outs, you have to take your best shot at moving that runner, whatever you think the best shot is. I guess that would fall under your "old school" description but it is done because of the current stats that it is more likely to score that run from 2b with 1 out than from 1b with no out and a weak hitter up. Who's up after? Who is runner?, what kind of pitcher? Etc., etc. all factor.
That said, If I've done it a handful of times over the years, it is more likely during a non-conference game that the hitter gave me a weak effort the first few times with hopes of being able to hit away. This sends the clear message that that won't be tolerated.