Should XTC Sue Toby Keith?

Another "SHOULD" post.  Another "You stole my 3-4-5-8" post.My last post was about two (2) songs that both featured the same four (4) notes -  3-4-5-8  - prominently in their choruses/hooks.  The songs were

Toby Keith - Red Solo Cup (2011)Sebastian Mikael - Last Night ft. Wale (2013)

I raised the possibility and reasons why these songs could be in litigation. I did NOT take a side - my purpose was to be illustrative and solicit responses.  I heard "Last Night" by Sebastian Mikael for the first time as I was driving home from the airport in Nashville Sunday night (February 23, 2014) and couldn't help but notice the 3-4-5-8's jumping out of the car radio._______________________________________________________________________Today I ask a related question and what would be a precedent to the Toby Keith v. Sebastian Mikael possibility  - namely, should XTC sue Toby Keith for stealing their 3-4-5-8?

XTC  Then She Appeared (1992)Toby Keith  Red Solo Cup (2011)

XTC's Then She Appeared (1992) is a song written and recorded almost twenty (20) years before Toby Keith's Red Solo Cup (2011).  It also prominently features the 3-4-5-8 melody.  The 3-4-5-8 is the opening vocal and hook throughout the entire song.The thirteen (13) examples of 3-4-5-8 in Then She Appeared, complete with associated lyrics, are heard here:XTC - Then She Appeared  (1992)

0.22  then she appeared0.31  then she appeared0.50  cherubim cheered0.59  then she appeared1.08  then she appeared1.26  know it sounds weird2.02  then she appeared2.11  then she appeared2.30  all Edward Lear-ed3.06  then she appeared3.15  then she appeared3.24  then she appeared3.33  then she appeared

The sixteen (16) statements of 3-4-5-8 in Toby Keith's Red Solo Cup (2011):

0.32  red solo cup0.35  I fill you up0.44  red solo cup0.47  I lift you up1.19  red solo cup1.22  I fill you up1.31  red solo cup1.33  I lift you up2.21  red solo cup2.24  I fill you up2.32  red solo cup2.35  I lift you up2.44  red solo cup2.47  I fill you up2.56  red solo cup2.59  I lift you up

_______________________________________________________________________Are four (4) prominent and clearly-heard notes in common between songs reason enough to instigate a copyright infringement lawsuit?  One answer could be found in comparing this hypothetical (or not) XTC v. Toby Keith music copyright infringement case to the actual Marvin Gaye v. Robin Thicke copyright infringement case in which NO notes were in common between the songs.If one can sue when the similarity is only STYLE and NOT melody, surely one is even more likely to sue when the similarity is MELODY and not STYLE.(Do any/all the tags in this post have any bearing on the merit of this potential copyright infringement lawsuit?)As always, I welcome your comments.