On the other hand; things might be broken already right now. If you look at the DNS-statistics on https://status.ntppool.org/, you will see little peaks[1] on the top the hour and some smaller ones every half hour. My guess is that these are cronjobs run with some sort of sntp lookup. Now think of a large ISP doing Carrier Grade NAT. All of a sudden these cronjobs are triggered, the ISP’s resolver resolves something like pool.ntp.org or 0.pool.ntp.org and returns (only) 4 A-records. The same four addresses will be used by all these clients (at one given ISP). Many clients will, at the same time, try to connect to them all at once from only a few IPv4 source addresses (because of CGNAT). There is a fair change this will trigger rate limiting. With AAAA-records in the DNS-response this could have been prevented, because there would be much more unique source addresses.
What I’m trying to say is: do not assume everything is working smoothly right now. The current setup is developing shortcomings too in an ever changing world and also causes some ‘brokeness’ here and there.
[1] The small peak probably represents a multitude of queries due to DNS-caching at the resolver level.