Radiator side-plug retainer -- clip or zip tie?

[Hendo]

Car is a 1982 Volvo 245 wagon. Non-turbo D24 engine.

The old plug was weeping some fluid, so I asked the shop about it when it was in for other work. They suggested replacing the plug and seal, and I agreed.

Shop is a long-time Volvo-only independent.

They replaced the plug and seal, but instead of the factory metal retaining clip, they used zip ties.

They said the metal clips can come lose or fail, so the zip-tie is a better alternative. But they also said they would install a clip if I really wanted it.

I presume that I would have a major coolant leak if the zip tie fails, and I'm not comfortable with that since I've had zip ties fail in other applications.

But I don't know much!

The old clip was at least 20 years old, and more likely original 1982 factory issue so I would think the clip is a better choice.

But I'm often wrong, so I thought I'd see what y'all think.

Thanks in advance!!

-Tom in SoCal