"DEL may be used as either a block-level element or an inline element."
coming from HTML 4.0 reference at WDG on DEL element

"These two [del and ins] elements are unusual for HTML in that they may serve as either block-level or inline elements (but not both)."
coming from W3C HTML 4.01 recommendation, Section 9.4 Marking document changes: The INS and DEL elements