They shouldn't be surprised if ads are shown more often.
This could turn into the online video equivalent of the Burma Shave road signs.
> Typically, six consecutive small signs would be posted along the edge of highways, spaced for sequential reading by passing motorists. The last sign was almost always the name of the product.
https://en.wikipedia.org/wiki/Burma-Shave#Roadside_billboard...
Yeah - it seems like this will cause a series of 5 second skippable ads that still sums up to >many seconds of unskippable ads (unless that's banned, in which case they will just see ads more often, as you say)
I expect it will make the experience worse rather than better because the publishers will try to maintain their inventory (how many seconds of ads they show per minute watched)