A tent on the beach, with no one living inside it, and just a solar panel which flashed at night to show any signs of use.
This is just one of the strange occurrences reported to UK Border Force and the National Crime Agency by the Coastwatch at North Denes, as the volunteer team work closer with official enforcement agencies.
Watchkeeper Roy Woods, 68, said: 'Obviously we can't say much because these things are confidential, and anyway we don't hear the outcome.
'But we've had a visit from UK Border Force and the National Crime Agency because with all that's happening with the EU, they want us to report anything suspicious to them.
'They only have 10 people to cover this whole area and they're based at Felixstowe, so they gave us instructions about what to look out for and what to do.
'We just inform them and they will come and investigate if they think they need to.'
Watchkeepers man the tower, close to Seashore Holiday Park, between 9am and 4pm every day of the year - including Christmas Day.
They log every movement along the coast, look out for anyone in distress and give advice to holidaymakers.
Mr Woods said: 'Last Thursday there was a family going down to the beach and the dad had a big inflatable double bed.'
He said he was worried the man was going to use it as a lilo in the sea, but luckily he was using it instead of a towel.
The Coastwatch's beefed up role comes as they received a £700 cheque from Persimmon Homes, as part of their community champions fund.
The money will go toward replacing the ladder at the watchtower.
Lucy Woodhall, Persimmon field sales manager, said: 'The Coastwatch touched people's hearts in the office, all the causes are great but people can relate to the benefits here.'
Mr Woods added the team were always looking for new volunteers. He said: 'We give up our own time and we never know what's going to happen.
'And that's lovely because volunteers can have an interest in anything from wildlife to radio communications and there's something here for them.'
• To get involved, call the Coastwatch anytime between 9 am - 4pm, Monday to Friday, on 01493 332192. Full training provided.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here