That request is definitely unusual, but there are a few normal, practical explanations that fit it better than anything mysterious.
Most likely reasons
1. Tamper / intrusion indicator
Wrapping a door handle in foil can act like a simple “seal.”
- If someone touches or turns the handle, the foil gets wrinkled or torn
- It lets them know if the door was touched while they were away
It’s a low-tech way of checking for entry attempts.
2. Hygiene / keeping the handle clean
Some people use foil when leaving for a long time to:
- Prevent dust, oils, or germs from accumulating on the handle
- Avoid coming home to a dirty surface
It’s not common, but it’s simple and temporary.
3. DIY protection during maintenance or paint-related reasons
Less likely, but sometimes foil is used to:
- Cover hardware during cleaning or polishing
- Protect finishes from oxidation or residue
What it is probably not
- It’s not a known security system practice
- It doesn’t block electronics, signals, or anything like that in this context
- It’s not related to any widely accepted “home safety standard”
Most reasonable interpretation
The most likely explanation is the tamper-evidence idea—they wanted a quick way to know if someone touched their door while they were gone, and just asked a neighbor as a favor without explaining the reason.
If you want, I can also tell you what other odd “vacation hacks” people do that look suspicious but have simple explanations.