It is not StackExchange's staff's, moderators' or users' responsibility to monitor 3rd party ToS violations.

So we should do nothng about it.

If Unity gets fed up, they'll give SE a call and SE will take care of it.

Further reading: Should moderators enforce NDAs for software vendors?

One of the tricky parts in here is how is the ToS interpreted.

Unity also provides a downloadable software component (the “Unity Software”),

Here, the "Unity Software" sounds to me like it is what you download from Unity's web site: what you use to edit and program your game and what you use to build your game; not the games made with Unity.

In this case, the ToS would not apply to these games and modding a game made with Unity to remove the splash screen would totally be legitimate.

Now perhaps the game they're trying to mod has their own ToS which prevents users from removing the splash screen, or modding it altogether.

As a side note, IANAL, so all of this second part might be rubbish.

It is not StackExchange's staff's, moderators' or users' responsibility to monitor 3rd party ToS violations.

So we should do nothing about it.

If Unity gets fed up, they'll give SE a call and SE will take care of it.

Further reading: Should moderators enforce NDAs for software vendors?

One of the tricky parts in here is how is the ToS interpreted.

Unity also provides a downloadable software component (the “Unity Software”),

Here, the "Unity Software" sounds to me like it is what you download from Unity's web site: what you use to edit and program your game and what you use to build your game; not the games made with Unity.

In this case, the ToS would not apply to these games and modding a game made with Unity to remove the splash screen would totally be legitimate.

Now perhaps the game they're trying to mod has their own ToS which prevents users from removing the splash screen, or modding it altogether.

As a side note, IANAL, so all of this second part might be rubbish.

It is not StackExchange's staff's, moderators' or users' responsibility to monitor 3rd party ToS violations.

So we should do nothng about it.

If Unity gets fed up, they'll give SE a call and SE will take care of it.

Further reading: Should moderators enforce NDAs for software vendors?

It is not StackExchange's staff's, moderators' or users' responsibility to monitor 3rd party ToS violations.

So we should do nothng about it.

If Unity gets fed up, they'll give SE a call and SE will take care of it.

Further reading: Should moderators enforce NDAs for software vendors?

One of the tricky parts in here is how is the ToS interpreted.

Unity also provides a downloadable software component (the “Unity Software”),

Here, the "Unity Software" sounds to me like it is what you download from Unity's web site: what you use to edit and program your game and what you use to build your game; not the games made with Unity.

In this case, the ToS would not apply to these games and modding a game made with Unity to remove the splash screen would totally be legitimate.

Now perhaps the game they're trying to mod has their own ToS which prevents users from removing the splash screen, or modding it altogether.

As a side note, IANAL, so all of this second part might be rubbish.