This "two channel 10s" question surfaces every few months and the answer remains the same:
For the 85-90% of Boston DMA viewers who use cable, satellite or OTT streamers to get their TV, there is no confusion. They tune to "channel 10" (or just "NBC" on streamers) and they see NBC for Boston. The vast majority of them don't get WJAR at all, or if they do it's because it's significantly viewed in a few communities south of Boston and shows up somewhere in the high 90s.
"10" was chosen because it didn't conflict with anything else on the Comcast systems that dominate the DMA. There are other channels that already had use of 3 and 8 on many of the systems.
As for the 10-15 percent of Boston DMA viewers who use OTA reception, only a small minority of THOSE, mostly south and a little bit west of Boston, can get WJAR's 10.1 over the air. So we're down to maybe 3 percent of the entire DMA that actually faces real-world confusion between "NBC 10" from Providence on 10.1 and "NBC 10" from Boston on 15.1.
Then there's Bristol County and nearby areas that are in the Providence DMA. They don't get WBTS on cable - it's too new to get SV status and as a class A license it's not entitled to SV anyway - so the "NBC 10" they get on cable and satellite is WJAR that's home to their market, and only if they have OTA reception is there a possibility they might also discover the other "NBC 10" on 15.1.
And most viewers - nearly all of them - just don't think as deeply as we do about all of this. If they want to watch Fallon or Sunday night football or whatever, they turn on the "NBC" that exists for them on cable or satellite and probably don't think any further about the matter. Half of them probably don't realize NBC left channel 7, or even channel 4!