Hotel security

[Daz]

Handy little bit of kit to help secure your hotel room. Bit more pricey than a rubber door wedge but has the advantage of quick release. In times where unfortunately we have to consider active shootings in public areas, little security devices like these assist in the Run, Hide, Tell advice by UK Government. Also helpful for lone travellers who want a little extra security in hotels.
DoorJammer Portable Door Lock Brace for Home Security and Personal Protection (DJ3 - DoorJammer (Standard)), Red : Amazon.co.uk: DIY & Tools

[Pitts]

If you need to improvise something I often use my lock-knife by jamming it between the door and the frame, or like a door stop. Not as effective as this, but slows the entry down enough to be out of bed and running

[Daz]

I always encourage my wife and daughter to take rubber wedges as they're cheap and easy, but can be difficult to remove if the door has been forced over it. Good tip about the lock knife, not heard that before.