As varinhas normais podem ser ganhas através de lutas não-mágicas?

Sim

Pode-se certamente ganhar a lealdade de uma varinha ordinária, subjugando fisicamente o seu usuário. No caso da varinha de Malfoy, que Harry pegou dele fisicamente, Ollivander sugere que ele ganhou sua lealdade.

“I took this wand from Draco Malfoy by force,” said Harry. “Can I use it safely?”

“I think so. Subtle laws govern wand ownership, but the conquered wand will usually bend its will to its new master.”

—Harry Potter and the Deathly Hallows

Da mesma forma, Ron arrancou a varinha de Peter Pettigrew dele:

“And we’ll have that,” whispered Ron, tugging Wormtail’s wand from his other hand.

—Harry Potter and the Deathly Hallows

“So I should use this one?” said Ron, pulling Wormtail’s wand out of his pocket and handing it to Ollivander.

“Chestnut and dragon heartstring. Nine-and-a-quarter inches. Brittle. I was forced to make this shortly after my kidnapping, for Peter Pettigrew. Yes, if you won it, it is more likely to do your bidding, and do it well, than another wand.”

—Harry Potter and the Deathly Hallows

No entanto, é apenas o Elder Wand que considera o poder como a única coisa que importa. Uma varinha comum provavelmente terá algum apego ao seu usuário anterior, com o grau dependendo de vários fatores, incluindo os materiais da varinha. Por exemplo, varinhas de cabelo de unicórnio não alteram a lealdade tão facilmente, seja fisicamente ou com magia. De acordo com este material do antigo Pottermore:

Unicorn hair generally produces the most consistent magic, and is least subject to fluctuations and blockages. Wands with unicorn cores are generally the most difficult to turn to the Dark Arts. They are the most faithful of all wands, and usually remain strongly attached to their first owner, irrespective of whether he or she was an accomplished witch or wizard.

Além disso, como alguém adquire uma varinha pode importar. De acordo com Ollivander:

“Hawthorn and unicorn hair. Ten inches precisely. Reasonably springy. This was the wand of Draco Malfoy.”

“Was?” repeated Harry. “Isn’t it still his?”

“Perhaps not. If you took it—”

“—I did—”

“—then it may be yours. Of course, the manner of taking matters Much also depends upon the wand itself. In general, however, where a wand has been won, its allegiance will change.”

—Harry Potter and the Deathly Hallows

Eu acho que sim. Por exemplo, Harry ganhou a varinha dos Elder junto com Draco de Draco - que ganhou por desarmar Dumbledore - apenas arrancando a varinha dele.

He leapt over an armchair and wrested the three wands from Draco’s grip
- Malfoy Manor, Harry Potter and the Deathly Hallow

resultado com

"... This was the wand of Draco Malfoy.”
“Was?” repeated Harry. “Isn’t it still his?”
“Perhaps not. If you took it —”
“— I did —”
“— then it may be yours. Of course, the manner of taking matters. Much also depends upon the wand itself. In general, however, where a wand has been won, its allegiance will change." - The Wandmaker, Harry Potter and the Deathly Hallow

Quando Harry se infiltrou no Ministério da Magia (em Relíquias da Morte), ele testemunhou Dolores Umbridge interrogando uma bruxa nascida trouxa. Umbridge continuou tentando torturá-la para admitir que ela havia roubado sua varinha de um "mago nascido". Harry encontra um número de magos cujas varinhas foram confiscadas pelos seguidores de Voldemort que assumiram o Ministério da Magia. Tudo isso implica que tal coisa é possível.