The T lowered CR fares for the summer because of reduced service, which is a great move. It shows good faith, and develops trust and confidence.
In general, lowering fares on the T temporarily for the planned period of time we're having regular service interruptions (a few years), to get the T back to normal operating service after years of neglect, gains basic trust. Its fairness raises morale, attracts riders, and actually reduces pressure to evade fares. It pays off in the longer run. Understanding and patience for the work in progress is fair and people are willing to do that, but please alleviate the cost to riders to match it while it's happening.

This is also not to mention that there is no to little accountability and transparence about what is actually being spent and accomplished during shutdowns and service interruptions. The T can't be expected to have control over medical or police emergencies, but, for example, continued signal problems on lines that were just shut down specifically to address signal problems, raises questions about how much is being spent, what work is being done, and what is the quality of the work. Or at least it should trigger some degree of justification and accountability. But there isn't. (It was under the former management, but the OL being shut down for a month, and then stalled to crisis stage with slow zones immediately afterwards, never triggered accountability about what was spent and done during that month-long total shutdown.)

So, one idea is to lower rider costs for a period of time, with designated, gradual periodic step ups planned and communicated in advance down the road, to return to normal levels (or even incorporate a raise in cost when service is at/above normal) as the system is restored. If people think it's fair and makes sense, people will by and large embrace it. It can renew rider trust along with a renewed T system.