Assertion:
If you use a BR at the end of a block structuring element (ex: BLOCKQUOTE) or block structuring sub element (ex: LI), you may need to use two consecutive line breaks to produce a visual space in a document. This is because there is already an implied line break at the end of block structures.

Simple table:
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TD Cell 1TH Cell 2
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Simple table with one BR at the end of each cell:
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TD Cell 1
TH Cell 2
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Simple table with two BRs at the end of each cell:
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TD Cell 1

TH Cell 2

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