I have pieces from original sets, but there are also many imitations, such as Chinese sets, which were bought for me as a child, because small Lego sets used to be very expensive at that time, while large craft sets were cheaper.
I would think the issue would be for obviously non-lego pieces. Not knockoff stuff, but like, K'Nex or something clearly not interoperable.
I wouldn't clock any of the pieces in that picture as non-standard, personally.