It won't be good PR for those bus companies who decide to cease being part of the £2 fare scheme when it's going on.
Especially in the areas where there is competition, when one operator is £2 singles, the other operator is back to standard fares.
It won't be good for drivers working for those bus companies who make such a decision. I still hear drivers explaining the scheme to passengers, who sometimes remember that they've been told about it before. What chance them remembering the June deadline? There will be passengers getting on with their two pound coins, maybe even putting them in the hopper if it is an exact fare operation, only to be told it is now £3.60, or whatever, which they won'y have because the fare was £2 last week. There will be passengers who ask for a single, because the return fare is over £4 - unless the driver quickly questions them to ascertain whether they will be coming back, they will be irate when they find they are out of pocket (and the bus probably late).
Any Forum members who are drivers for these companies might want to find a good reason for not being in work on 3rd July (any holiday leave owing?).
Such companies will need to indulge in a hell of a lot of publicity to make sure their staff don't have withstand a lot of complaints, and, maybe, abuse, particularly in areas where some companies are retaining the scheme.
In turn national government will need to publicise the end of the scheme (or any variance of it) more widely than they did its introduction. It is much much easier to start a scheme like this than to end it.